How to deal with anxiety? I’d appreciate any tips.

Hi I’m 21 and in the graduating phase of my Uni life and I start randomly getting extremely anxious to the point where I’ll start feeling a pit in my stomach that starts hurting. It’s not any sort of external pressure just self inflicted I don’t want to keep feeling like this and going in these cycles I’m very scared I’ll give myself an autoimmune disease if I don’t learn to regulate myself better. I’d really appreciate any help and tips.