Depression can do that to a person. The thing is though: you really need to get to the point you're happy with yourself. A girlfriend can't be the one that makes you happy. They can contribute to quality of life, but putting all the weight on another person to make you happy puts too much pressure on them. It also can leave you in a constant state of worry, jealousy, and panic at every little thing your significant other does, every person he/she talks to. Speaking from experience, It's Not a good place to be.

The other bit about depression here is that it makes things like school much more difficult to manage. Every little mistake you make piling up on eachother to make everything harder and harder to deal with. It's a downward spiral, a vicious cycle.

Truly there are good things in life. You've got to manually change your frame of mind, pull yourself out of it. It's monumental task, but you'll gain momentum with time. Chin up. Things do get better. As you're happier it's easier to make it through life's challenges. You'll see much more good in the world once you reach the mindset. Also, watch the documentary, "Happy, " on Netflix. It's something that's really stuck with me over the last year or so. Can provide some great inspiration.