I get the feeling you are in the middle of a massive storm where you have had your confidence battered by others just when you were at the age when you needed a safe perch? Life is so brutal at times created by the very people you would have thought more of. But do remind yourself that just because you have had a difficult few years at school it doesn't mean life is all like that.
Often (if you decide to go to Uni) you can find hundreds of people from all over the world, who share the same interests you in what you study, or outlook etc. Those people all have a life story and they can help you put perspective on your life so far. What you think has been bad, others would think it's a walk in the park. Find the cheer leaders around you who encourage you. Get a list of the subjects that really are so interesting you think you want to study them for life. Then explore every job - by what it needs (ie communications and interaction with others, or technically based interaction with scientific gear) working inside or outside, surveying, flying, sailing, farming? It's ok not to like people or indeed never to have to bother to cosy up to anyone. Some people love animals far far more than any human. Humans can be vindictive, smelly, violent, unpredictable, dishonest, uncaring, selfish, sadistic, remote, callous - do you get the picture? BUT for everyone like that (and they are usually damaged goods themselves because they have been hurt and unhappy in their heads) there are hundreds of people who are kind, gentle, calm, honest, caring. Do you get the picture? NOT EVERYONE IS LIKE THAT Your head and psyche is unique. You will think on a different wave length to so many others. But when you find that certain someone who thinks and speaks on the same 'wavelength' it is like music that just is harmonious and beautiful. You just have to hold onto what you know, what you love and hope along the next few years you can explore that and find those certain someone's who will help you enjoy those subjects even more.
Manage your emotional health first. Get into a stable and positive mind set. Use all the help you can get from school, your GP, college - both talking therapies and medication if it is warranted. But a lot of the time it is just accepting that is how you feel and it is normal for what you have experienced. Knowing you have a bad head space is like a storm. The rain comes down, it is cold wet and horrible. But the sun always comes out eventually. When it does it feels so good. It sounds like you need some help maintaining the positives (think of 3 every single day - and being upright and breathing might be one of them!) Then start the escape and dream what you would love to do. No holds barred - as you fall asleep imagine you are the most popular person around. Imagine yourself in the role you want to do. No pressure from anyone. See it. What are you doing? What are you enjoying? How do you see yourself? Hold that imagery and in the daytime research it to see what you need to do and whether it is achievable.
The pressure from parents can be immense because they want you to be a brain surgeon or a rocket scientist on a big salary, blah blah and it is so black and white. But the reality with medicine is that it is no walk in the park. The pressures on you for at least your Uni years are massive and then 10 years plus to get to consultant stage are off the scale. People are the stressors, and when they are in pain or hurt they say the worst. Often they want to sue. So if you can't hack the pressure now pre exams, you could find you don't have the emotional reserve before you start. Why is medicine the be all and end all? You can do a lot with science grades - use your school/college career service to explore jobs and careers. So don't think you have to do all the decisions now. Some Uni's will still take mature students aged 30 plus as long as you are fit and healthy.
So take each step at a time. Deal with today. Remind yourself what you did well, what made you laugh, smile. Have a plan or timetable to manage your day tomorrow. Try not to look too far forward. That is the crucifier. Then when you have finished any exams start the searching again, and explore. Take time to visit Uni's to get a feel for each campus. Good luck. You are doing so well. Just never look back, because if you have done the very best you possibly can today you can't do any more.