Career/ degree advice

Any advice much appreciated,
I’m a year 12 student taking a levels maths maths, further maths, physics and french. I did well at GCSE with 9 9s and 3 8s but have been struggling so far this year (predicted abbc). Always planned on engineering at a top uni but have gone off that idea having looked into it more. I feel as if I could have done different a levels which I would have been stronger in ( English, history etc.) but I’m stuck with what I’ve got now.
What are my options for degrees from my a levels?
I’ve looked into studying economics at uni but know nothing about it and feel as if I’d be disadvantaged for not taking economics a level.
Would I be seen as a weaker candidate for not taking a level economics for a top uni?
And what options do I have?

Oh boy. Where to begin with this long question...
I did well at GCSE with 9 9s and 3 8s but have been struggling so far this year (predicted abbc)
Yeah, A Levels tend to hit you like a brick. It's still early days though since you're 3 months or so in. Things can change in the space of 6 months, so it's difficult to say whether you should stick at it or change subjects.
Also A Levels are very very different to GCSEs. If you approach study the same way as you did with GCSEs, prepared to get very very humbled.
I feel as if I could have done different a levels which I would have been stronger in ( English, history etc.) but I’m stuck with what I’ve got now.
Whilst it's 3 months or so in, you still have time to change subjects and catch up should you wish. I personally would advise against that because you have 3 STEM subjects and French which would allow you to go in a myriad of degree courses. However, if you don't like the subjects and you're not getting the grades, then it's a bit redundant to keep studying them. Your call though.
What are my options for degrees from my a levels?
This question entails a long winded answer.
With Maths + any 2 A Levels alone, you can do:
With Maths + Physics + 3rd A Level, you can do:

Further Math is particularly helpful if you want to apply for a quantitative degree at a top end uni e.g. Maths, Economics, Computer Science, Finance, etc. Do note, for some courses where they are looking for well rounded applicants (i.e. not for quantitative degrees), having FM alongside with Maths (don't know a situation where you won't do FM without maths in college) would count it as a single subject for variation purposes, so you would need physics and French to be considered as a candidate with 3 "different" subjects (they have a similar problem with Economics + Business, English Language + English Literature, History + Ancient Civilisations, etc.).
With French, you can apply for joint language degrees (namely those with French), but you will struggle to get onto modern language degrees that ask for 2 European languages. You should have no problems with degrees in other types of languages e.g. Asian languages, African studies, Latin studies, etc. Linguistic degrees won't ask for A Levels in any subjects.
You can then apply for degrees that accept 3 A Levels in any subjects, which includes:
Conversely, should you do English and History instead, they are only requested for some degrees in English and History. You can still do degrees that accept 3 A Levels in any subjects, but you won't be able to do the ones that ask for physics, French, or 2 sciences.
I’ve looked into studying economics at uni but know nothing about it and feel as if I’d be disadvantaged for not taking economics a level.
Whilst not having Economics at A Level may mean you are not as familiar with Economics at degree level, you are far from being disadvantaged. Economics at uni is not like what they teach you at A Level (style-wise). You get a lot more models and theoretical debates as opposed to discussion on the applications of models (to my understanding of it).
Having Maths + FM would set you in good stead for any economics degree in the country. Economics A Level is not a requirement, and you're not expected to have it (especially when not all colleges teach it).
Should you wish to look through relevant books that might help you get a basic understanding of economics at degree level, let me know.
Would I be seen as a weaker candidate for not taking a level economics for a top uni?
See my answer above.
And what options do I have?
Not sure if this is supposed to be a separate question pointing to something else or it's a repeat of your question above.