Please help!

I know how you feel =/ this guy that I used to like flirted with loads of girls even after he sinabi he loved me, and it made me so jealous that i scared myself!I started to hate the girls he flirted with...but I should have hated him. I also found out that he had a gf, and that he was just stringing me along....he still tries talking to me but i refuse to socialise with a bastard like him.
Jealousy can be one of the most unpleasant feelings ever,not only do you feel guilty with yourself for feeling this way but also you feel that you can't tell anyone because they will think badly of you :S but hang in there :)
Eventually you will forget about him, and someone will come along who is perfect for you! So there is no need to be upset :D also you shouldn't worry about being popular! I used to worry about it all the time (back when i was in school :L )but honestly, just forget about it and do what you want to do, you'll be much happier.
So, my payo to you would be to ilipat on, start up some new hobbies, meet new people and, should you find someone else that you like...tell them! Because we only get one life and its a fucking short one, so you may aswell give everything you've got to make it a good one!
I wish you luck :)