I understand about the backfiring part. I can sometimes get very scared when I'm really happy. Just because I know what evil lurked just around the bend. I knows it's hard, but do your help to let yourself be happy when you are. Enjoy it. Take pictures and write down reminders describing your happiness. It's the happy times which make the bad times worth it in the end. While you are depressed, you might not feel it's worth it..... But the next time you are in the moment you will feel different.