What do i do about this situation with my ex bf??? how do i get him back?

Let it go. If you don't act like yourself when your with him regardless if your doing it on purpose or not is not good. If someone doesn't like you for who you are then what's the point of being with them. You sound young and shouldn't be spending so much time worrying about guys. I know that's easier said then done. But you have the rest of your life to date and worry about it. Take this time to have fun and figure yourself out. I started dating someone when I was 16. Now I'm 25 and we just broke up. I have to start out all over again and it is not easy. I wish I took this advice when I was young and just had fun. Now I have to try and figure out who I am all over again. Have fun while you can.