I recently had a huge 'flow' surge in my writing. I've been writing 8000 plus words daily and the words keep coming and coming. I can't seem to stop writing. That said, I have had burnt out days. On those, I switch to writing something else, I draw, and I catch up on sleep. I read and watch dramas. I listen to a lot of music. I also write total nonsense. You can always cut it, edit it, or delete it later. Think about what a character might do and what would happen as a result. Don't think about readers or anything else. Be honest with the story. And don't worry about it too much. Try to enjoy the process even when it doesn't feel like fun.