What's worked for me in the past is be calm, approach the person, ask if they have a few minutes to talk in private, and ask "I've been sensing you are unhappy with my work performance. If so, how can I improve? Do you have any suggestions? I'd like to resolve this so we can have a better working relationship." If you feel comfortable with this, then go for it. I have found when I am direct in a non-confrontational manner, I get better results. Good luck!
