I take myself out and get myself an ice cream or a soda
lol
Probably not what happens, but it's been a while since i've dealt with that kind of situation. The more times it happens to you, the better you learn to cope with it, but it's also proportional to how much you like the girl that you broke up with. It's always hard, who said it wasn't, but there's plenty of fish in the sea, unless you are determined to think that she is the one, and you think you can do better if you had a second chance.
Just know that sometimes that won't happen, and you just have to get back to reality and learn from the mistakes that lead to the break up. If it's a good thing in your case, then you may want to try at the most just being friends. It might be hard for you to be around her while you're only friends, especially if she gets over you sooner than you can get over her, and she already likes someone else. Seen that a few times too lol
But it's always good to keep a friend in your life, they are the people you know you can count on if they are true friends in your life.