life regrets after a levels

so I am in year 13 and just sat my a levels doing biology, chemistry and English literature. My course of interest is veterinary medicine. I currently have an offer for bio veterinary science where I can then do a post graduate for veterinary medicine, on reserved list for Vet medicine (little chance of making it out) , or I will take a gap year.

It all depends on that paper.

In year 11 I had to choose between two passions of mine, fashion design and veterinary medicine.
fashion design was a passion of mine from year 9 and I have always loved fashion, even now I'm always thinking where can I buy my next best outfit so everyone can stare at me. At the end of year 11 I got an overwhelming passion for animals to the point I just want to EAT THEM ALL (cute aggression its a thing).

At year 11 GCSE's I decided to choose initially for a levels, Biology Chemistry EnglisH Literature and Art.

But one of my teachers stopped me and told me "we recommend doing 3" so I ended up dropping art. When I rejoined a new teachers line, he didn't stop anyone from choosing 4.

At that moment of time I wanted to be a vet more than fashion, I loved animals so much I wanted to kiss them all and say that you are loved.
I gained work experience in relation and have a strong background in related to it.

During the period between a levels and results day, I've been scrolling on TikTok and seeing fashion school kids and my whole body fills with jealousy and then regret. I started searching online for courses and they all said 'preferably a levels in art and photography' and a portfolio which I have none. Compared to other students I am severely lacking, its not like I can go back two years and rechoose my a levels.

At this moment in time, Im wanting fashion more than vet school, and I am starting to deeply regret my life choices! Is there any options for me to pursue fashion or do you think this a phase I will get over.

Firstly in general, I would not recommend considering bioveterinary science as a starting point to do veterinary medicine as a graduate. Unlike medicine and dentistry, there isn't much if any funding available for doing vet med as a graduate, and most students (I expect you included) probably wouldn't be able to pay for 5 years of tuition fees +/- living expenses, at least without having worked for an extended period of time saving a lot of money (the kind of money that could get you a decent house somewhere as well...). Even for medicine/dentistry which have some funding allotment for doing it as a second degree it's not recommended - I think for vet med unless your family is wealthy enough that it doesn't really matter what you do and you just are expected to do something, vet med as a second degree as a graduate is likely a non-starter.
Secondly I'm not sure your framing of loving animals and how you love them is necessarily a strong indicator to pursue vet med either, although I'll admit I have somewhat more limited knowledge of this field. However while I could be well wrong, I can't imagine it's all rainbows and happiness and would think it involves a lot more mud and/or heartbreak. So that might be a consideration.
Finally regarding fashion: not doing GCSE Art isn't necessarily a barrier. It's very typical for applicants to creative arts degrees to do an "art foundation", called a FAD course - especially for design disciplines like fashion with limited representation in the A-level Art syllabus. This is a 1 year further education course (i.e. like A-levels or similar, although may be run through colleges or some universities), where you just do art/design work for the year, usually initially work across a range of media and approaches then specialising in some particular area as you move on. As a FE course it's free if you're under the age of 19 at the start of the course (or possibly, 19 or younger? I'm not 100% sure of the cut off point anymore), but you don't get any funding from loans or similar so most just do it at a local provider.
You can read a bit more about FAD courses here: https://www.thestudentroom.co.uk/showthread.php?t=5017684
I might suggest, if a gap year looks probable anyway - embracing that, taking the opportunity to do a FAD course while you still shouldn't need to pay for it, and also continue getting more work experience for vet med to determine which you prefer.
That said it's pretty late in the year to be trying to apply for FAD courses if you did your A-level exams this year so you might struggle finding one with places still, and you would likely still need a basic portfolio etc - if you've not done any kind of creative work since before GCSE then that's not likely an option immediately (although equally this might be telling about your motivation for that kind of work - plenty of people who do that just "part-time" through a single A-level, or just in their free time, still aren't able to commit to doing creative work "full time" in a degree or FAD course as it's quite a lot!).
Note as per the above FAD FAQs thread, it's important to note a distinction between a FAD course (also called art foundation) and a foundation year at uni (which is an integrated part of a degree which is not necessarily transferable to other institutions and counts as HE study and is funded and costs the amount as any other year of a degree), and also not the same as a foundation degree (not commonly available now but equivalent to an HND or DipHE now I believe). So do be wary of terminology on that front.
However to conclude this final note on fashion, I would warn there is a difference in being interested in fashion and appreciating fashion design as a consumer/audience, and actually being a designer yourself - that involves a lot more technical skills and knowledge, as well as commercial knowledge, than you may know (as it's typically I understand not just illustrating outfits - you need to actually plan out the design so that at some point someone can cut a pattern for it and create it and someone else can wear it, whether that is you or someone else).

Fashion related course foundation year? You can take this and then go on to a fashion related degree, its for people who essentially picked the wrong a levels
https://www.academiccourse.co.uk/foundation-year/fashion#

so I am in year 13 and just sat my a levels doing biology, chemistry and English literature. My course of interest is veterinary medicine. I currently have an offer for bio veterinary science where I can then do a post graduate for veterinary medicine, on reserved list for Vet medicine (little chance of making it out) , or I will take a gap year.
It all depends on that paper.
In year 11 I had to choose between two passions of mine, fashion design and veterinary medicine.
fashion design was a passion of mine from year 9 and I have always loved fashion, even now I'm always thinking where can I buy my next best outfit so everyone can stare at me. At the end of year 11 I got an overwhelming passion for animals to the point I just want to EAT THEM ALL (cute aggression its a thing).
At year 11 GCSE's I decided to choose initially for a levels, Biology Chemistry EnglisH Literature and Art.
But one of my teachers stopped me and told me "we recommend doing 3" so I ended up dropping art. When I rejoined a new teachers line, he didn't stop anyone from choosing 4.
At that moment of time I wanted to be a vet more than fashion, I loved animals so much I wanted to kiss them all and say that you are loved.
I gained work experience in relation and have a strong background in related to it.
During the period between a levels and results day, I've been scrolling on TikTok and seeing fashion school kids and my whole body fills with jealousy and then regret. I started searching online for courses and they all said 'preferably a levels in art and photography' and a portfolio which I have none. Compared to other students I am severely lacking, its not like I can go back two years and rechoose my a levels.
At this moment in time, Im wanting fashion more than vet school, and I am starting to deeply regret my life choices! Is there any options for me to pursue fashion or do you think this a phase I will get over.