Hi!! I've been researching medicine courses at top unis too as i just got my results too!
basically top unis want pretty much As at alevel (two a*s at cambridge, less at imperial and durham, idk about the rest).
Medicine degree alevels are Maths, Bio, Chem, Physics, F.Maths that kind of thing. Compulsory alevel is chemistry then two of (maths, bio, physics). So your gcse results are good enough to do a levels in all these subjects and GOOD ENOUGH FOR TOP MEDICINCE COURSES! Yay! I'm not intent on medicine just researching tbh
p.s. it says on the cambridge website that after looking for A*A*A alevels, they want at LEAST 5Bs or above in GCSE SO YOU'RE FINE!