The most common thing a person would do right after being dumped is panic.
The same might just apply to you.
You'd probably try all means possible to reach your ex to try to figure out why things ended up the way it did, and subsequently try to patch things up if it's at all possible.
Just sit back and think things through for a moment, is it really wise to constantly put yourself in your ex's face? The both of you might be feeling hurt at the moment, with emotions at all time high.
When in each other's company, the both of you might have committed mistakes which could return to haunt the both of you in the future.
You just can't work through these problems when the both of you are always together.
If you really want to win your ex back, the best way to do it is to take a break from each other, for at least a month.
At this moment, get your emotions together, devise a plan to get your ex back.
Give room for your ex to do the same.
While spending time away from one another, it allows the both of you to think straight and look at the situation entirely.
You should feel less stressed when your ex is not around you at this point.
If so happens your ex is a classmate or a co-worker, be polite and don't take things too personal.
If you're able to get your emotions straight without the company of your ex, you might just recover from the breakup with little pain left to endure.
Surely your initial goal was to get your ex back, you might just realize that you do not really need your ex after the one-month break.
If you still want to get your ex back, your chances should be higher by now.