Why is university so draining?

Some of this might be an issue of perspective - 60% is a 2:1. If you're unsure of how to improve even after reviewing the feedback, try going to the office hourse for the lecture to discuss your assignment in more detail
I'd recommend speaking to your personal tutor also about how you're feeling especially in terms of feeling unsupported - they should be able to help guide you!

Sorry to hear about your health problems, and that your mental health has taken a battering. I'm guessing you may not want to say what condition you have or which uni you're at? (There's no pressure to!) Some unis are better than others at reasonable adjustments and some are downright shite tbh
You say you feel you've contacted everyone. Do you mind me asking if you're a home student and if you're receiving Disabled Student's Allowance for your condition? Do you have a mentor who could advocate for you/kick people up the butt? I'm also wondering who you've talked to about your mental health - as it would be sad if that spiralled and got out of hand.
As has been said, 60% is a 2.1. I feel you might be putting a lot of pressure/high expectations on yourself. First year is all about adjusting to uni and learning how to do the work to the level expected of you. Don't be too hard on yourself
Finally, regarding your personal tutor (who doesn't sound that great). Document all interactions with them and, where possible, try and keep conversations in written form (emails/Teams chats) only, so that there's a log for proof if needed further down the line

Hi! I have spoken to my personal tutor, nothing was really done, they just almost blamed my condition for it really even though I have sought every avenue of help. This time I got a bit below sixty, while my last assignment was rougher because of my condition and as the test was online, my condition wasn't really treated the way it should've been in an exam hall in terms of the layout of the assessment. I did bring this up to my tutor and they said it was my fault despite me already previously arranging access arrangements for exams. I'm so burnt out and honestly, I haven't met anyone here with my condition. I feel like I burden everyone and I have no clue what to do, I just keep failing.

Sorry to hear your personal tutor isn't much help here - I'd recommend getting in touch with the student union in that case if your personal tutor isn't supporting your reasonable adjustments for your condition as they should be doing that honestly. The SU may also be help support you and should be able to help advocate for you too hopefully
If you have a documented health condition which your university as agreed reasonable adjustments for, they should be delivering these though. I appreciate it can be really draining trying to push for that if they uni isn't supporting that actively though, having had similar experiences before

Hi there! I have CPTSD so university is very hard for me. The university I go to is I would say quite welcoming to other conditions, but because of the lack of people with my condition at around my age in the university, I feel like they have no idea how to treat me or help me. My assessments have been extremely difficult and due to recent events which have retriggered my condition, I have found it very hard to go to lectures and start strong this term. Sometimes I feel so out of place and as if someone like me with my condition shouldn't be here simply because everyone is uncomfortable around me and no one really knows how to treat me. My assessments have been extremely poor so far and I feel so disheartened honestly.

Ohhh, CPTSD is a very hard condition to live alongside, I feel for you. You've done well to get this far, and it doesn't sound like your assessments are extremely poor if you're averaging around 60% atm? But I can understand why you are exhausted and disheartened. It is really hard to self-advocate when you have conditions that zap your energy and make places, people and things in general feel unsafe.
There'd be no shame in dropping out and trying to find a better/more suitable uni for you: unis are supposed to support you and it doesn't sound like this is the right uni for you. Not because you're not good enough or not trying hard enough, but because they don't sound willing to support you. Also the Open University might be worth looking at?
If you decide to keep going with your current, I think the suggestion of involving your SU is a good one. Also any specialists/GPs you see, and a DSA mentor if you have one. And if you haven't applied for DSA and you decide to stay at uni, and you're a home student - please do seriously consider Disabled Student's Allowance. It was the difference between me dropping out of my Masters and not (I have mental health conditions too!), and I daresay I would have performed a lot better at undergrad had someone advised me to look into DSA.
Although I don't have CPTSD myself, I can somewhat imagine how draining and disheartening this all is for you. (I had a two-year disability discrimination complaint against my last uni, which was a horrible experience ) Please remember that health comes first and whatever happens, you can - and should! - hold your head high

They told me I should've self-regulated my own exam despite me being given no prior instruction on how to regulate it etc. I just want to drop out

I've been trying to do well. It's so hard to live with and I always feel as if I make everyone's life more difficult by being around me. Even relationship wise, no one can relate to me and my own condition and it's super disheartening. The issue is, this uni is well-known for their help services, and I'm going to feel so ashamed in dropping out because I've fought insanely hard to even live.

I honestly feel like I've contacted almost every form of support there is here. University is so hard, the assignments themselves are incredibly hard and I honestly don't understand how to improve as at best I'm at around the 60% mark. I want a 2:1 at least and it doesn't seem possible this year, it's only first year and I want to be competitive for other opportunities too, but I feel like such a failure. My mental health has fully deteriorated here as well, I honestly feel so alone and I've tried to talk and have set support up, but given my condition it's not enough. I have no clue what to do.

That is disappointing that a uni well-known for its support services is letting you down in this way I'm so sorry. That's super-heavy, feeling like you make life hard for other people. It may not be the easiest condition for others to understand, but that doesn't mean that you are a burden, or that people should treat you (or feel entitled to treat you) like a burden That's not fair on you! Like you say, you've fought insanely hard to keep living, and you're clearly trying to reach out for some help. So you're doing bits to help yourself, where and when you can.
From an outsider perspective, I have a sneaking suspicion that you put a lot of pressure on yourself generally. There really is no shame in dropping out - especially if that's more likely to help you keep going/living. You matter and your health is important, so it's really important to prioritise yourself and your emotional, physical and mental health needs at this time There's no shame in that whatsoever - take it from someone older (albeit not necessarily wiser) who's been a three different unis and seen the best and worst of uni mental health support (or in some cases, "support" in inverted commas!)

Thank you, I've recently got an assessment and got 60%. I honestly don't think I can get a 2:1 overall and am really worried about placement next year. I've taken some time out and time to go home now, but I'm honestly just not happy.