Everyone tells me their problems but no one listens to mine...?

It makes me feel so alone I guess. Everyone just pours out their sorrows and woes to me, and I try to help the best I can but it's hard to keep them happy. Especially when there's a problem that a bunch of my friends are all involved with, and I'm ALWAYS the neutral zone. For example, two of my friends really like the same guy. And all three people come to me for advice and to talk about it. One day I'll talk with one friend, the next day the other, and the next day the guy they both like. And honestly, it's SO exhausting. I try to keep up with them and keep everyone happy, but it's hard to keep one happy without cutting down the other. This always happens, but no one ever has the time to listen to whats troubling me. In fact, sometimes they make FUN of my problems! I'm constantly getting teased about a guy that's obsessed with me and won't leave me alone despite my numerous times telling him I'm not interested. I'm flattered that they come to me, but it wouldn't kill them to return the favour every once in a while. i just want everyone to be happy but I don't know how to keep them happy, and I don't know who has MY back...I don't know what to do, please help ! =[