im sorry to hear about your difficult situation, i hope you can find a way and things get better for you.
your gcses are fine to medicine. they may seem not the best, but a lot of med schools do gcses as a min requirement, and no scaling, with at least x grade in y amount of subjects to make it. i think the 5 in physics should be fine, but check for any schools you are interested in if they check all 3 sciences, or check 2 only, or any, whatever combo.
most med schools to my knowledge want chemistry required with a 2nd science (generally bio) and any 3rd subject. no a level is seen "better" than any other a level as long as it is within criteria. it's good you have chemistry, but psychology like you said can be troubling. is there any way you can swap over to biology? it may be a lot of content by this point that was covered depending on how your sixth form paces through the course, but if you've got the will then i believe in you. really try to push with your sixth form if they resist.
i recommend practicing well for the ucat, getting good work experience and volunteering (and write everything you see, learn, and understand from those experiences, you won't remember them after 6 months), making a great personal statement and doing well in your a levels. if anything, you could also try graduate entry medicine by doing a related degree e.g. biomed and then applying for medicine.
you've been through the low, now the only way for you to go is up.