It's very common when user's run one cycle in proximity to another. Odds are, your progest receptors were active after SD and PP (they stay activated for long periods of time after these types of cycles).. You'd have been fine, but after running Epi it suppressed your estrogen and further sensitized your PR. Hence, Progesterone rebound.
I suggest starting P5P and 1-Carboxy along w/ a SERM. This may not be proliferated glandular tissue, but rather PRL. My experience was w/ Trenadrol. After symptoms appeared ON CYCLE, I stopped, ran PCT of Clomid and some B6 to be safe, and a few weeks later got a very small lump. I ran B6 at 600mg daily (300AM, 300 pre workout, since prolactin is highest in the morning hours and during/post workout). I also ran PowerFULL and tamoxifen. Excellent success. So I waited a while, and ran epi for 4 weeks, the first 2 weeks I ran it w/ 25mg ATD EOD. I followed with Raloxifene for PCT, continued P5P and a long taper of 6-OXO and haven't had problems in the last 5 months.
EDIT: I suggest no more than 20mg tamoxifen. There's NO REASON to just start downing 40mg daily. I know SOME of the studies suggest 20-40mg for pubertal/accute gynecomastia, but it's MORE than necessary. Stick w/ 20 until it's gone, then taper off at 10.