I do the same thing sometimes. Get sloppy and have to go through my form all agian. Long ago, I told myslef when things are going bad, put it up. It really helps. I put the bows down, relax, and go through my form in my head and identify what im doing wrong. My biggest problem, and its been a reoccurring problem for many years, is to remember to release with back tension. Its easy forme to get sloppy and pluck my string.