Why Am I Extremely Lethargic With Profuse Sweating? Why Are Cysts Bursting?

i am 35 years old, i have been experiencing drenching sweating episodes, and extreme lethargy. I could be sitting with my kids reading a book to them and burst out in sweats. I have also gained about 40 pounds in about two months with no change in my diet. i took a pregnancy test and it was negative. i have had the IUD for two years now. I had an abnormal pap about two years ago and i am on recheck every 4 months. Sometimes i feel a stabbing pain in my lower left side and i believe those are the cysts bursting, this is something i have experienced since i was about 19 but have had four babies within 5 years, so that must be working right. :- ) I just dont know why i am so tired. Oh, i used to do the break through bleeding with the cyst bursting, but that has not happend now for about two months and with the IUD i would spot atleast one or two days out of the month but that has ceased over the last two months and now it is a thick clear discharge when the bloating for the normal period would occur and what seems to be menstrual cramps as i remember from my teenage years.