I have suffered through severe depression for the vast majority of my life, I have severe social anxiety, and still suffer from depression, however when I was with my horse, my depression seemed to vanish entirely. I was able to talk to people more easily when she was around. She I guess was my security blanket you could say. Without going into boring details that no one that doesn't know me really would want to hear, my depression was so severe that I'd often contemplated suicide and had it planned out, but, never did it, because my horse was something for me to live for. She was my life-line so to speak. When she died I had a hard time hanging on, for the first year I didn't think I would be able to be around horses ever again, but they're in my blood, taking away horse's is like taking away oxygen. I'm back into riding again through riding lessons for hunter/jumper, granted it's not the same as having my own horse, and it still hurts very much that I lost her, but I have to say being around them again is helping me through my depression again. If I wasn't able to be with my horse (in a similiar situation as you) I would be absolutely depressed, and when she foundered I was. Yes you have these other horse's you're riding, but it's not the same as if they were your own. Having your own horse, and riding someone else's is a completely different feeling. So yeah, I understand what you're going through, and it's tough as all manure. Just thought I'd rant a little to let you know that you're not alone.