I'm going to go completely opposite of what others are saying - I would guess your estrogen is TOO LOW. Yup, I said it.
I can't wrap my head around people that don't understand that your test to estrogen levels should be a balanced ratio. Why should a guy on 500mg test a week, with massively more circulating testosterone in his system have the same estrogen levels as a guy not on exogenous testosterone? That makes ZERO sense. That isn't balanced.
Personally I think AI is pushed WAY too hard on every board I frequent.
Using myself for example, I don't need any AI on 500mg test enanthate, and only experience mild water bloat. If I choose to use arimidex (liquidex), I do so for cosmetic reasons, and only use .125mg 2-3x a week, which is a very small amount.
Everyone is different, but I know that if I take .25mg of arimidex in one shot it absolutely tanks my estrogen and I feel almost depressed and like a colorless personality for about 24-36 hours afterward.
AI is strong stuff and should be tailored to the individual. Start LOW on the stuff and experiment with dosage and frequency.