Depression just doesn't go away unfortunately. You have days when you're fine, and then days where it just pops up out of nowhere.
On those days, I usually just smoke a shit ton of weed and keep my mind occupied with something.
Anything to get out of your own head. I don't recommend getting prescribed anti-depressants. It will take a long time to find something that works consistently,
and most of them have all kinds of fucked up side effects. Stay away from the booze when your depressed man, that shit will just bring you further into the hole.
Depression fucking sucks dude, I've lived with it my whole life and like I said, it won't just go away. But you can do things to curb it for awhile.