You need to pick yourself up, help yourself recover from it, be amenable. Here is some advice which will help speed up the process.
1. Cut them off, completely
Unfriend, unfollow, delete, remove. This is called the band-aid effect, you gotta do it all at once, it will come as a blow but you need to get them out of your sight. Even if you two have decided to stay friends, don’t do it immediately after the break up, it will confuse you, you will lose clarity of the situation and your feelings. If cutting them off is not possible, if it involves kids, same work place, neighborhood etc, then try to limit the encounter to its minimum.
2. Take your time and mourn
There is no such thing as ‘just get over it’, as much as we would all like it to exist, it doesn’t. You can’t just ask yourself to stop feeling something and your brain would oblige and the switch would go off. However, you can try and put a lid on it, but you will eventually break down and it will be harder regaining your strength from that. So don’t blame yourself for feeling sad, angry, hurt; whatever it is that you’re feeling, you are a human being not a robot, cry your heart out if you want to, just feel it! We all have different coping mechanisms, we recover at our own pace, so don’t compare your progress to someone else’s, don’t think you’re a weak person just because you’re taking longer than what you think is the ideal time to grieve, take as much time as you need, as long as you’re improving.
3. Accept it
As hard as it might be, you need to accept that it’s over and there is no going back. If you are the one who broke up, don’t try to rethink your decision, this happens when you start thinking about all the good times you had with your partner making all the reasons you broke up seem insignificant; or if you got dumped, don’t try scheming all the ways to get them back, you’ll lose your self-respect, try getting yourself back instead. Think of all the reasons you two didn’t work out, don’t obsess over it, make peace with it and make efforts to move in the forward direction instead of going backwards.