I need help coping through depression?

Well i've been feeling really down lately. The reason is i think about me just never being with girls. I mean i'm 15 years old and i've never dated a single girl. And whats even more sad to know is i've never kissed a girl and it just saddens me that i'm missing out on SO much. I feel so isolated with girls. I mean yea i occasionally talk to them but it's not that much! I don't even have a single girl on my contacts list on my cell phone. Just a feeling of being pathetic and missing out overwhelms me and it's hard to even get through the day. Yea, i have positive memories, but they're not enough to take over the stressful thoughts i have of being a loser.