When you're feeling down, stare at Silk's avatar for a few moment and you'll be cheered right up. I just did and now I'm anything but "down."
LOL. Okay, all laughs aside, I can relate to what you're feeling, smiler. But with a name like that, you could just about cheer everyone else up. That's one thing you could do. Take your mind off your own feelings sometimes and try to make someone else happy. Whoever you choose, they will appreciate it. I find that by focusing on someone else and making them feel happy, you're actually also making yourself feel good about making someone else happy.
Times can be tough and we all react differently to different situations and it can take us all different amounts of time to come through the other end of the tunnel back into the light. This is how you have to see these moments of depression. There is a light at the end of every tunnel. If you're self-harming, it's no longer just a bout of "feeling down" but possibly a serious case of depression. I'm not a doctor but it sounds serious to me. In your own best interest, seek the help of someone you trust or perhaps a medical professional. You don't need to be hurting yourself.
Keep writing your poetry. Keep expressing yourself. If you are feeling things emotionally and you are doing something contructive, you are living. You are focusing on something and taking your mind off the lonely times and the times you are feeling down. You gotta move it or lose it. Last of all, you deserve to be happy! Sometimes people don't feel deserving of the world around them. But the truth is, everyone deserves to be happy and they deserve to be loved.
Good luck to you, smiler (or if you're like me, keep staring at Silk's avatar