I think a fear of going crazy and getting out of control is a huge concern for a lot of anxiety sufferers. It seems to be that not having control over life or situations is a major underlying trigger for anxiety, at least for me I know it is... I can't control if I get cancer, I can't control if someone will crash into me and kill me on the highway, I can't control if a terrorist decides to blow up my plane, etc..... So I can certainly see how fear of going out of control yourself and "losing it" could be a fear as well! Its a tough thing do deal with... are you in therapy or anything?
"You cannot hope to build a better world without improving the individuals. To that end, each of us must work for our own improvement and, at the same time, share a general responsibility for all humanity, our particular duty being to aid those to whom we think we can be most useful." - Marie Curie
"The pessimist sees difficulty in every opportunity. The optimist sees the opportunity in every difficulty." - Winston Churchill