Although you are really upset after the break up, and are aching to be with your ex again, change the situation, and make your ex want to be with you again.
In fact, if you use the right strategies, your ex will become absolutely desperate to be with you again.
The very best thing you can do is to simply leave your ex alone and do nothing right now.
It does sound like ridiculous advice, but rest assured, it WILL work.
Because of the terrible state you are in now, after the break up, you need to see to your own needs first.
It is very likely that your health is suffering because of all the trauma of the failed relationship.
For instance, you are probably sleeping very badly at the moment, and your eating habits have probably changed drastically.
This is also a reason why you need time away from your ex.
Make every effort to get yourself back on track again.
Sometimes it is even necessary to see a doctor after a relationship has failed, so, if you feel that you cannot cope on your own, do this.
Take whatever the doctor prescribes for you - it can only help things to move along a lot faster, and eventually make your ex want to be with you again.
Also, work on your physical appearance as well.
Get yourself back into the shape you were when you and your ex first met.
Remember, he/she doesn't know what you are doing, and will really be amazed at the dramatic change in you.
This wont' be for long though, because your mutual friends will see just how great you are looking, and word will definitely get back to your ex about this.
In fact, your ex will hear such good, positive things about you, that he she will begin to get really anxious to see you again.
The arguments of the break up will be a thing of the past, and your ex will make every effort possible to contact you and suggest that the two of you get back together again.