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Hello and thank you for using JustAnswer. The best way to move on would be to try to try to start dating again and going out with your friends without him so that you can distract yourself more and more away from thinking about him. In addition, other techniques to help you move on would be to write a letter addressed to him where you explain everything you are feeling and thinking, do not hold anything back. But instead of giving him the letter you want to dispose of it in a fashion that you find cathartic, such as burning the letter. This will be a cathartic exercise to help you move on both literally and figuratively.
Another technique you can use would be a thought stopping technique. Here you wear a rubber band 24/7 and every time you think about him you want to snap the rubber band. This would create a mild pain that can help remind you to focus your attention elsewhere and also your brain will start to associate mild pain with him and will try to prevent you from thinking about him in a self-preserving manner.
Here is also a good book that uses Cognitive Behavioral Therapy (CBT) principles to help you move forward with your life:
"Getting Past Your Breakup: How to Turn a Devastating Loss into the Best Thing That Ever Happened to You" by Elliott
Overall the best solution is going to be time for you as that is what it takes to successfully move on after such an abrupt end to the relationship.