I was probably around 35 years old before someone told me I was not subject to my thought life.  I didn’t realize that, when my mind would wander over into strange territory, that I could control my mind and stop it from going into those places.  You can have a barrage of terrible thoughts hit you all at once and you will become what those thoughts are if you dwell there.  When those thoughts come toward you, I like the old adage that says you can’t stop the birds from flying over you, but you can keep them from building a nest in your head.  Do not give life to negative thoughts.  Rebuke them in Jesus name.  Take authority over your thought life.  Pray in tongues and think about things that are lovely, pure, and true.  Do not allow negative thoughts to live inside of you.