I don't know what to do.

Everytime he looks at me or talks to me, I think about the old times and I don't want to remember those times. They hurt to bad to remember. And he just up and out of no where tells me he loves my smile and that it's beautiful? Why does he do this to me? Like I'm not already an emotion reack and have trouble dealing with keeping it all in. I don't like telling people things. It's a pain to keep up with it. I can't take it. I fall apart way to easy. And then it takes me awhile to get back up and try to start over again. His ex was my best friend. Now I don't even talk to her because she was stuck up his a-hole. And his bestfriend likes me. I like his best friend too. But I was with him and it hurts to see him. I don't look, talk, or think about him and I'm use to it being that way. It became a habit. I'm not ready to give up my wall to get hurt again. I built this wall BECAUSE of him. Not because I felt I had to. I KNOW I had to, and it's his fault. :/ I need help.