You need to loosen up and have practical goals and expectations. Don't sit down and try to write "something good" or to "make a bunch of progress" on what you're working on. You going to sit down to write. Just write something, anything. That's the bar for success: just to write. You, like many if not most, have trained your brain that if you can't sit down and write something "good" you're a failure. You need to retrain your brain.
You also need to have some goddamn fun. Get with someone and write a paragraph, then they write the next paragraph, then you the one after that. Alternate back and forth like that. You have to deal with whatever the other person includes in the story. And you both just write whatever absurd thing needs to happen to keep the story going. And just start it with something simple, like a character going to the store to buy something. Hijinks ensue.
You also need to have some goddamn fun. Get with someone and write a paragraph, then they write the next paragraph, then you the one after that. Alternate back and forth like that. You have to deal with whatever the other person includes in the story. And you both just write whatever absurd thing needs to happen to keep the story going. And just start it with something simple, like a character going to the store to buy something. Hijinks ensue.
What's the takeaway? There's gotta be a better way to make myself get shit done than abusing myself. The thing is, that's all I'm really comfortable doing.