I was in a very similar situation to you! I'm an A level student and know it is super hard to decide what to do with your future at such a young age. I have decided on environmental science degree and career personally by thinking about what I'm interested in really carefully and deciding my key goals. For me that was sustainability and helping the planet.
If you feel able to, talk to family or friends about your concerns. They might be able to help you think about what your strengths are and how you can capitalise on them career-wise.
I would also think back-what have you enjoyed doing for a long time? You can think about whether your A levels are related to any careers that you might be interested in. Some universities have a 'careers' section on pages for their degrees. Indeed also has a lot of job advertisements on their website, so you can look at what jobs require educationally.
I won't say follow your heart as so many people said that to me- I would think, but I have so many conflicting feelings! My advice is play to your strengths, think about what you will enjoy doing and what you love, and then think about careers related to that. Also remember nothing is set in stone and there are loads of different options for career changes. Good luck!