I have lived with depression and anxiety for over twenty lears now.
The one lesson that I can tell everyone is that you CAN beat it.
I can't lie - it is not easy, in fact it is probably one of the hardest things to do because it requires a profound shift in thinking and self-awareness, and it is really really hard work.
However, eventually you can get to a point where you recognise that "the problem" (as I refer to it - Time Bandits style) is creeping up again, and you get early enough warning to stamp on it and get it sorted before it takes a real hold.
Keep your chins up everyone. It's Bastard hard work, but it can be beaten!