I took Biology and psychology as well, it is a lot of work (Biology especially) and if you dont enjoy it or are not interested in it, then you won't have the capacity to focus on it and study enough to get a good grade.
I took the wrong alevels, hated them, but my parents wouldn't let me change. Ended up failing, developed severe depression and eventually got expelled (because I hated the subjects I would act up, and then fell behind so acted up more, and so on in a cycle until I got expelled).
When I started a new school, I finally took subjects I loved and was interested in (biology, psychology and English) and was so much happier and ended up getting really good final grades this summer.
No subject is going to be a walk in the park, but i promise you just take subjects you enjoy, even if they seem they dont go together, and the next two years will be so much better.
Finally, at my new school I was originally taking chemistry but swapped it for English in January. Despite missing a whole term of it I still came out with a good grade, far better than I would have for chemistry. Its never too late to swap.
I hope this helps and good luck,