Sounds like Estrogen.
Get some Bloodwork done, so you can see where your Estradiol is at.
Did this just start during PCT, or was it going on near the end of your Cycle.
The more Info you can provide, the easier it is to give you an answer that will be helpful...................... JP
P.S.
If you have some Aromasin on hand, 1/4 Tab (6.25 Mg) every other day should help ~ but you need that Bloodwork.
Can't do this with Arimidex, unless you reduce the dosage down over a couple of weeks.
Stopping it suddenly can cause Estrogen Rebound, so if you were using it as your AI on Cycle, and stopped suddenly.
Then this is indeed the problem.