Back to the rut. You're not writing. The only thing you're doing is feeling sorry for yourself. Days go by. Maybe weeks. And then a few months have gone by and you're self-esteem is dwindling as your self-loathing is increasing.
That's when it really gets bad because you're starting to become immobilized with fear that you'll never find another good idea or that even if you do, you won't be able to finish a draft or if you do, you won't be able to rewrite it or rethink it. That kind of thinking pushes you down even further into the miasma of a blocked writer.
Oh, by the way, that's what you've become. You are not a screenwriter anymore. You are now a screenwriter who can't break through his block and that's dangerous territory because with all that free time you have because you aren't writing, you can spend it "thinking" about how you're not writing and that brings you down even more.
Is there a way out of this horrible place?
Only if you change the rut you've been in. How do you do that? Depends on your psyche. Maybe take a short vacation. Or a long one. Get away from your environment and the daily bullshit. Join a health club. Exercise can be a very freeing experience once you find a routine.
I won't kid you. There are might be 50 things you can try to get out of your rut and none of them may work. But you have to try.
You have to change whatever pattern you've fallen into.
Because nothing changes if nothing changes, you have to take that first step.
If you don't, it'll only get worse.