u/helly0jelly

I have been practicing this piece for almost 3 years and have reached a good level of technique and musicality. However, when I try to play it up to let's say 80% of the actual speed it should be, things get messy and unclear. I think because it gets overwhelming in my head that it reflects on my playing. I don't have many problems in technique but Prokofiev is just another beast. I love the piece and want to nail it. Any tips?