Anyone just help

Alright so the deal here is that I have a guy bestfriend and I started liking him and so did he we had a thing for a little bit but than that went down hill I still have hella feelings for him but he’s talking to other girls he talks to me as if nothing ever happened and he was just my best friend he will be with other girls and i will get really jealous i haven’t seen him in a long time I just miss him what do I do I wanna tell him something but I don’t know what! 😭💔☹️