I relate to every word you put down. What helps me is realizing that I cannot be extrinsically motivated. A bad grade or loss of points means nothing to me and has never motivated me. Motivation has to come from within - and sometimes that means I have to gaslight myself into being motivated. If I have an essay I don't want to work on I will stare into space and repeat to myself:
"I am compelled to work on my essay for 5 minutes"
Within a few minutes of looking like an insane person I will cave and get to work. But it gets even better, because the hardest part is always getting the ball rolling. Once I get 5 minutes in adding another 5 minutes on top of that is much easier, and once I've worked for 10 minutes, whats another 10 minutes? before I know it I'll have been working for an hour and it will feel amazing. This isn't a surefire way to get productive, but if you have adhd it's great to make a list of strategies for yourself to use in the future.