It's Like My Best Friend Died

Have you ever felt like you don't matter? There aren't many feelings in the world that are worse than that. My whole life I have tried to think of others. I admit that I have probably failed at that a time or two but I am always trying. I'm always trying to be better and to do better. However, I feel like nobody cares. In the past year I have experienced the highest high when I gave birth to my beautiful daughter (or had her cut out of my abdomen, whatever) and the lowest of lows. I have had some really good friends turn their backs on me. And the worst part is, I don't know what I did. All of the sudden I am feeling such joy and they weren't there for me. I have reached out to no avail. Now I'm trying to find a way to cope. It feels as if they died and it's really hard to lose them all at once.