I really want to switch a levels

I’m already 4 months into a levels and desperately want to switch from biology to psychology (or honestly anything else but biology) I originally chose biology because wanted to do medicine and to ‘keep my options open’ but i realised i probably won’t like medicine if i don’t like biology and many medical schools would have accepted maths chemistry, psychology (my original choices) if i had stuck to that. Now im going with law but i cant help but feel i may get a bad grade biology since i got a 6 at gcse even though i got 8s and 9s in my other subjects and wont be able to get into a top uni.
Not only is biology difficult i have no interest in the subject and hate the content. My head of year said i can only drop it if i have proof of it affecting my mental health but even then id be doing only 2 alevels.
I feel so stupid and should have just stuck with my original options because i hate biology, but any advise would be really really valued.