I feel incredibly lonely?

Sometimes I feel incredibly sad depressed and lonely Like no body wants to hang out with me or talk to me. I have friends but I don't think they care about me as much as I care about them it seems like they never listen to me when I really need them, I'm always there for all of them when they are sad but when I'm sad they just leave me by my lonesome and hang out with others. I'm totally in love with this boy at my school I've never felt like this before sounds a little cheesy and stupid, but I really Like him he's quite and funny. But he likes someone else, a really popular girl that had a lot of friends and is pretty that I could never value up to. I don't see anyone ever loving me because there is always someone with better looks, personality and everything else than me. None of my friends understand me and I don't dare talk to my parents about this because they will most liking put me in therapy. I dot want to go to a mental institute. I don't see myself as very pretty just average, thin and pale skinned. I don't know what to do the only thing I have to look forward to is maybe one day getting close to the love of my life and my best friend that I don't see alot but is the funniest person on the planet and makes me happy. But even er can't understand my depression. I get the urge to cut myself a lot and do drugs but I don't because if my life sux already indent want my body to go down the drain too. Sometimes I'm very happy and when I am I have alot of energy and do and say things with out thinking this usually results in me embarrassing myself in front of the boy I love and other people. Then I go back to being depressed and feeling utterly stupid. It's a vicious cycle that never ends. I guess I'm just looking for advice or something I dint know what to do or where to turn, I guess ranting on here won't change anything but I don't know what else to do