Had lap surgery and started prometrium

Allie
I have been trying for just over 10 months. Had the lap surgery ( originally for a polyp) back in April and found a bunch of endo. I started trying again in May, nothing yet. 
Since the surgery I have had brutal pains around what would be ovulation time - never had it before the surgery. I seem to be still spotting for about 5 days before every period. 
Starting this month they put me on prometrium (progesterone) at 400 mg a day for days 14-35. Which confused me bc I normally ovulate later that day 14. Day 15 of this cycle came and I had the bad pain. Then on day 24 spotting occurred just like normal - I was frustrated bc not only was I not pregnant but the prometrium wasn't seeming to stop the spotting. Here I am day 28 today and yesterday the spotting stopped. Not only did it stop but it seems to be turned back to regular looking white cm. I am ultra confused now, I had my mind convinced this month didn't work, then I thought well maybe it's the prometrium starting to work , then I think it could be implantation bleeding ..... I took a test this am and a negative ... But it's just 13 dpi so who knows 
Has anyone with end had the surgery and been trying different things since ... My fertility specialist said that the first 6 months after surgery there are higher chances ... Studies have shown after 6 months (after surgery) the chances go down a lot .... 
Has any used prometrium - how do you feel about it ?