I am sorry you are having these problems but also interested in your post. I have been on Anastrozole for just over a year and have been experiencing worsening panic attacks and uncontrollable feelings of impending doom and uncontrollable crying for the last six months or so. My cancer diagnosis was very similar to yours and from the viewpoint of clear mammogram etc all looks well. Whilst I have had a history of panic attacks previously the current attacks are off the scale. I am becoming increasingly concerned that Anastrozole is key to these symptoms and will hope to discuss this with my oncologist at an upcoming review. I feel it maybe that patients who have previously diagnosed panic/ anxiety conditions may be more likely to experience these more extreme reactions. Possibly this could be a fruitful area for research into the side effects of AIs.