i also know how you feel. as i came to the end of my nursing career i knew inside that i couldn't do the job anymore. i'm sure if i would have tried to keep it up i would have been let go. i know they were documenting things i didn't do right but i was also mad that i hadn't been in the loop.
perhaps your boss, isn't this also his job responsibility, could try to help brainstorm ideas that could help you do the job better. and, if you could relieve some stress about your work you might perform better.
can you get another position in the same company?