Crush has a new boyfriend and i need help.

Hey guys,
So i'm in high school and I've had this crush on one of my friends for about a year. It wasn't that bad until a few months ago. When the crush first started she was already in a relationship and I didn't think much about her, i just kind of liked her. But after she broke up we really started talking and my feelings kept growing and growing but i could never get the courage to tell her. Then i thought i was getting somewhere when i was able to take her to homecoming and we had a nice time. At the dance she told me that there was a guy who she was talking to and i knew right there that i never had a chance at all. They started dating the week after and i got used to it and was ready to accept it. But last week they became boyfriend-girlfriend and its just really hard to see them together. She posts three or four times a day about how great he is and what he does for her and i know this is normal for new relationships, but i can't get over it. They're really good together and I'm really glad she's happy, and i know that i need to just get over it and that's where i need help. I can't stop thinking about her so i need some tips on how to just forget about her and move on.