Distract yourself.
Retrain your brain: when you want to contact him on social media immediately do something else. Repeat this reconditioning behavior until it becomes automatic.

Time is the only thing that will heal your anxiety about your breakup. And, it's what you do with that time, that speeds up your healing process, or slows you down.

You have to go through the whole emotional process of your breakup. You can't just speed dial it to "healing" and be over him. Our human physiology won't allow that. You will go through lots of emotional ups and downs until you reach the point where thinking about him doesn't trigger your desire to contact him. Then, you'll get to the point where you don't even think about him.