I think arachnophobia.kid is right. A lot of the time, to move forward you have to take a step back and see if from a different angle. Try new things. Adventure and do stuff that you normally wouldn't do. Depression is a fun sucker. It steals the joy that you feel and hides it and usually we wander around just super frustrated and wonder where it has all gone. But a lot of things are found when you aren't looking so the best thing for me is taking the time to try other stuff. I've started creeping through university buildings looking for secret passages and doors left unlocked and just exploring. Maybe set up an elaborate over the top prank at your workplace. Or start a project that the past you would have enjoyed and see how it goes. Play a video game you know is terrible just to see how it turns out. Watch a movie that's genre you usually avoid like the plague. Busy yourself and add new experiences to your belt and eventually you'll find that joy again.