I don't know how..

Melissa
So I been messing with this girl for 3 years and recently I pointed out that I wanted to be in a relationship and she doesn't, so we've stopped talking and now i don't know how to move on or how to make myself feel better, I'm feeling so down and depressed about it.. I feel like I've wasted three years of my life on someone that didn't take me seriously.. Any suggestion on making this easier?