Good State Of Mind

I had a thought today. I'm thinking that I won't be truly happy until I get a "Good State of Mind". I was thinking about the things in my life that I could improve and all the things that I really wanted happened. And if all those things do happen I wondered if I wouldn't be depressed anymore. I thought of it, and nothing would change. I would have everything in my life that I wanted and still be depressed. I'd have to be mentally happy to become physically happy. That is the one thing I don't know how to fix.