I don’t know what to do….

I don’t know what to do with myself anymore. I have become horribly depressed. Even the antidepressant I am on doesn’t seem to be working anymore. I’m very unhappy at work, I think having to deal with miserable people all the time there has something to do with that though. One of my closest friends cut me out of her life because "she doesn’t need another mother." I keep telling myself that it doesn’t really matter, but maybe it does? I don’t know. I just don’t know what is wrong with me. I don’t like the person I’m becoming, the person I’ve become. I’ve become very mean, uncaring, indifferent. I know something has to change, but I have no idea how to do it.