Unfortunately, this is all trial and error, so this is something you're going to have to discuss with your psychiatrist. It's possible that you haven't found your med yet, as you're still this depressed. I'd also recommend if you're not already doing it to get into therapy with a psychologist and see if you can't actually cure this thing rather than treat the symptoms. Augmentation is hard because with every drug you add you're also adding side effects, and you only augment drugs that are working but just not well enough. While that sounds like you, it still might be that your base drugs are simply not working for you. Problem is, if you've been on tons of meds, there might not be a whole lot left, but that's a question for your psychiatrist and you to figure out.