I'm not familiar with the UK system, but could you attend classes at a college with smaller class sizes? That sounds like it might be a problem for you. Also, do you see a counsellor? Have you mentioned any mental illnesses you may suffer from to see if you can get accommodations?

Finally, do you want to attend college? Many people don't and go into the trades, for instance. University is not the only road to success.

I failed college once. It sounds like the first time you dropped in advance (so you didn't fail), and this second time you're still a student. So I wouldn't take it as failure. If you don't have a therapist of some sort I would look for one (probably easier to find as a student, and more affordable), and discuss what to do.

It sounds like you don't want to give up. You're not at the end of the road yet.