Relationship issues

So my bf broke up with me bc we had a rough spot but we talked about it and were trying to be together again but he tokes this other goes (freshman) to the prom, and he’s a senior may I add. I think we all know what happens at prom and yeah I’m upset, he promised he would text me to tell me he’s okay and how everything is kin by he blew me off, I said it was okay and for him to just text me when it was over and he was safe at home, he never did so I was up all night worrying about him. I finally get a little sleep and he’s posted pictures of him holding her and smiling, you may not see th big problem but he never smiles, I had to beg him to smile for me at last years prom and he only would once and he did for every picture with this girl. I was hurt and she posted pictures of them hugging and holding hands saying “prom with him🖤” he told me nothing happened but everyone said they saw them go to a back room for a while, I’m really hurt please give me advice or something