First of all to let you know, anxiety changes the chemistry of the brain causing these thoughts. Medications given by doctors are the best because they get your brain chemistry back for temporary time, but if you took it for a long time with the right instructions, you will be able to defeat anxiety. Now the second thing is when you get any negative thought remember that it is from your brain because you are suffering from anxiety. And when you think in a positive manner you will succeed in getting your emotions back on track. For ex:- if your boyfriend dose not answer a call, dont think he is cheating you and breaking up but think that he is busy. This i promise you defeating anxiety. My mother was able to defeat anxiety with out even any medication but by positive thinking. So Be + not -.