What has become my fear

I think about my sanity far more than it is healthy to. Every once and a while I meet somebody and think to myself “how do I know that this person is not just in my head.” Oddly it is not the idea of insanity that bothers me it is the fact that I can not longer trust reality. It is the fact that I could be perfectly sane and be condemned as insane. It is the fact that the person telling me that I am insane might not actually exist. It is not good that these are the things that I think about now. It is not good that this ill-trust of reality is the only thing that I can thing of that frightens me anymore. It is not good to fear your own mind. What am I hiding from myself?