post breakup sucks

so my bf broke up with me a couple months ago (he was my 1st bf). I always thought I would be the kind of person that didn't care and would just be able to move on np. but no! it makes me physically sick to just make eye contact. I go to a small school so I see him several times a day. i literally haven't said one word to him since and i feel bad, but I can't help it. after winter break I saw him and I had a full on anxiety attack. ADVICE PLZ!!! I need to just move on but Idk how!