Broken-hearted?

Yesterday I found out that this guy that I had been consistently talking to was also trying to work things out with his ex girlfriend. I went to a mutual friends house to hang out and saw them together and she was on his lap so he didn't even care to tell me before I saw it for myself. This definitely sucked and I'm still in a lot of pain but I wanted to know if anyone had ideas on how to move on and let something like this not affect you very much because I have been having a difficult time. I know that every time I color my hair I feel like a new person so as dumb as that sounds I thought about doing that. Any advice would be greatly appreciated because this has truly impacted the way I see myself and it sucks.