I feel a lot of religion in these responses. If you can bring yourself to believe in God, certainly that's the easiest way to believe you have meaning and purpose. In that case, there is something that cares about you when you've lost belief in yourself.

Some of us can't actually believe in God. If you can't believe in or rely on God, you need to talk to someone. I'm an open-minded atheist, and I've got nothing but time and a lot of experience with philosophy and depression. I'll listen, here or via private message, if you think that might help. Good luck.