Is this an overreaction?

[Rebecca]

I read my boyfriend's facebook messages (i know, not good) and he and his friend were talking about going to uni this year and how they will hook up with loads of girls. He also told his friend that he would ditch going to the same uni as me if they went together. I know I wasn't supposed to read it, and I sort of freaked out to him afterwards about uni even though he doesn't know I read his messages (logged out now, couldn't take it anymore). I now overreact about everything and am really sensitive to small things that he does or doesn't do. Otherwise he really is a pretty nice guy and treats me well. Should I end it or how do I find a way to be positive and forget his stupid conversation?