My GF of 6 months broke up with me. We are both cool with it, but I hold out some hope she may miss me....?

you guys didn't break up over a serious matter so it wouldn't be too hard for her to give you another chance. a girl being in a relationship for 6 months may have already developed strong feelings for the guy. Give it a week (or two) for her to think everything out, then talk to her and ask her to reconsider the relationship you two have. if she still doesn't change her mind, wait for about a month or 2 and if she hasn't changed her mind by then, you're out of luck.