What do I do? I REALLY NEED HELP!!!!!!!

Ok, I have this ex-boyfriend that I love more than anything and he still loves me. But he left me for some ***** that he doesn't even like, well he tells me and her that he loves her too, but I don't believe it for a second. He used to be so nice and caring and wouldn't leave me alone and now he doesn't want to talk to me or have anything to do with me because this girl says not to. Well this girl doesn't like me what so ever and never has and her best friend told me that shes only doing it to make me mad. I'm really confused I've talked to a teacher and my ex today and I was hoping it would make it better but it didn't. it' been going on since Monday night and everyone in the whole school thinks he is making the biggest mistake of his life. So do I. I still love him though and I really need help. I was crying and so the girl was laughing at me and so I've stopped since Tuesday and keep holding my head high. Her best friend said that if I keep it up that she will lay off and not find it funny. But it is so hard not to cry and I force myself to laugh and smile and all my friends see that and it's really hard and when I'm at home all I do is cry. I'm really tough and I never ever cry so this is really affecting me. I want him to take me back more than anything in the world, I've prayed and everything. I know that if it's meant to be he will come back but I want him back now. I sent him a really long text today after school of exactly how I felt and hopefull it helps, but I don't know. I just love him a lot and really miss him. Please help me!!!!!!!