How do I get my girlfriend back?

So over the months I've had this problem were I get really jealous of my girlfriend. Say if she's talk to another boy or goes out and hangs round with loads of girls and boys. I will start saying nasty things, letting the jealousy get the better of me. Anyways last night it happened again and I kept questioning where she was and what was she doing? Thing is I know I can trust this girl like I know she wouldn't cheat, that's what I know but my mind thinks different.

I woke up this morning and she was really pissed off and said it was over and that she's not having a control freak tell her what she can and can't do. She was saying its best if we move on and all that then after a while she came round abit but said we was on a break and that if she wanted to talk to other boys than she will. It finally hit me today and now I realise how pathetic and stupid I actually sound. Why did I do all that stuff when I knew from the start I could trust her? She started talking to me normal again before she went to work but she says she's still on this break. I just don't know what to do. I really don't want to lose her and I realise what I did was wrong. Just the thought of her talking to another boy makes me feel sick. How do I get her to change her mind and work things out with me?