What Causes Nausea And Fatigue After Periods?

Hello. I am a 27 year old female, and I have had irregular to non-existent menstrual cycles since I was 16. At 20, I finally found out I have PCOS. Six days ago, I started experiencing a dull, aching pain in my right pelvic area that would come and go in waves. I also noticed that there was a bulge in the area that would flare up and go back down. I experienced a little nausea for a couple of days, and then I started my period this past Tuesday. It is not a normal period, different color, not very heavy, and very tissue-like. I become very nauseous yesterday, and noticed that the flaring bulge is present again. I do take provera every three months to start a cycle, but last month I saw my doctor, and she wants me to take it every month for a few months. So I took it last month, and had my cycle for ten days, and then this month, this whole thing has started. I just feel like something is not right, with the bulge, feeling nauseous on and off, feeling depleted of energy, etc. Any help would be greatly appreciated. Thank you!