If this was me, I'd check in with my primary care doc as all of these symptoms sound like they might also be an unrelated infection--viral or bacterial. That is, if you have a flu-like illness or even an atypical UTI you'd have these symptoms. If you are not additionally ill, the doctor might have advice too if this is the anastrozole. Personally, I have come off my AI for brief "vacations" and never had symptoms. Wishing you the best!