Need some advice, trying to get it together please help?!?

I am 19 yrs old :) soon to go back into school. Here's the deal I have always thought myself to be independent untill a year ago when I decided to move in with my at the time "boyfriend" now its been 7 months after our break up and he's already moved on and I find it quite difficult to do so. I admit I made a mistake in moving in so young and now I'm having a really hard time focusing when emotionally I'm not stable. How do you stay focused?