Not enough information.
Where did you purchase the arimidex? Who made it? How much have you been taking?
Some guys, like me, have a terribly hard time keeping estrogen under control. I have no idea why, but even a little bit of any aromatizing steroid and I almost immediately have all sorts of issues that come from over-high E2. I have to take AI in MUCH higher doses than what is usually recommended here for anyone ever.
This is not advice, as I really do not know your situation and it is probably not good advice for almost anyone. But, for myself, when I have issues such as yours, and I often do, I usually take an overly large dosage of AI for a few days and this takes care of all of my problems within about 2 days. Then I cut back to a more "normal" dosage of AI until things start to get ahead of me once again.