I overcame my suicidal tendencies by trying to die, and realizing I want to live
I haven't overcome my 'depression' if I can call it that. Like a lot of others here are saying, you just live with it, you always carry that stone with you, and hopefully it becomes more bearable as time goes on. Things that help/helped me cope are standard shit like:
having to struggle surviving
having a goal
having lots and lots of self-centred 'me' time
making other people happy
taking moments to enjoy/appreciate what I have: crisp air on a breezy day, clean and cool water when I'm thirsty, products and services that I could never create for myself, the overwhelming scale of existence.
"I feel like any good times I have are just mocking memories for me when I’m down" reminds me of a quote from a movie: "I've felt the best life could offer, and from this point on I'll only be able to feel lesser versions of what I've already felt". Yeah not so inspiring....but nonetheless I think we should appreciate what we have, and perhaps that at least we aren't living in perpetual pain or something. I had serious infections from eczema for a month and I was in so much pain I couldn't even walk. Going through that I can always be happy that I'm not suffering like that, and helps me appreciate things more.