I found out the guy I liked used to have a crush on this other girl and now I'm feeling all down?

I know the feeling. I had a guy that I couldn't stop thinking about and at one point it almost took over my life. Then one day while I was camping, a girl came up to him and told him about my crush on him. Honestly, when things like what happened to the both of us happen we should just say to ourselves that it's not worth it. It's their loss. One day that girl might just leave him and then he'll come crawling back. But honestly we both know we can do better than that.