To do medicine in Bulgaria you still need A level chemistry and biology with at least C/B grades in them. Also, doing a foundation year medical degree in the UK doesn't seem like an option for you as you need A level Chemistry with at least an A grade in it. So, the only way to do medicine is with that a level chemistry.

Also, if medicine is something you've wanted to do forever than you should've known what it takes to do it way before choosing your a level options. But, if medicine something you really want to do don't give up on it you could always do medicine as a post graduate or even take a gap year or two and get that a level chemistry as well as relevant work experience.

Good luck!!