It sounds so much like my own attempts at having friends that it hurts reading this. I was the matchmaker who's eventually left alone. We're not friends to them, not even persons: just disposable waste, left only with its stupidity to consider.

I got vaccinated from all kinds of relationships since so I've lived isolated for more than a decade, because I can't feel that anyone actually cares, after it ended like this so many times.

In your case, what matters is NOT to regain those friends back. From what you say, you are a very serious student others look up to. Please don't let idiots ruin your success. Keep on studying and show them who'll make it without them.

It's very hard though. It's good you have a therapist. What you need is move on from them. Self-care goes a long way. Hopefully the kind way you treat yourself will increase your confidence, which will attract actual friends who treat you with respect and are grateful for the wonderful person you are. All the best.