It sounds like this work situation is not the greatest for you :-) I would find another situation where I felt the people either were more genuine or at least were not under-the-bus types?

One thing I have learned is that other people cannot hurt us if we know who we are and are genuine. Someone else calling me a liar does not make me a liar. Someone else saying I did or said X, Y, or Z does not mean I did or said that. If I work in a place where other people do not see that I am honest and take another person's word about my behavior rather than looking at my behavior, I do not want to work there!

A nit-picky boss would be just a lot of noise over my head. If it was uncomfortable to work there because of my past experiences and/or I had not learned to be "myself" yet and handle it, then I would move on to somewhere else, would make a different plan for my work life, start working on doing something else, somewhere else. Set a date to get out of there and make a plan to follow to get elsewhere.