I messed up and I just need to vent.

I messed up with someone and things were said and there was a lot of immaturity and bad timing. Him and I have been friends for 4 years finally we start talking but hes going away to college and so am I so we decided it was just kinda for fun no attachments. But then his friend is one of my close friends and we hung out then I invited the guy I was talking to to hang out with us but he said he was busy so his friend and I decided to hang out at the beach and nothig romantic happened I just needed to vent about some stuff. But the guy I was talking to got jealous after I asked him if it was cool with him 5 times and he said yeah its cool so then I thought it was okay. The next day he was making it a big deal and he said how would you feel and at first i didnt understand or see But then i finally saw that yes it looks a little weird and I apologized repeatedly and now at school he avoids me and cant even look at me. That was 2 months ago and today was my last day of school and he still wont speak to me. He knows im leaving and I just want to make amends. Ugh. I got attached after I said I wouldnt and it sucks because hes blocked me on everything and still avoids me.