I have Fibro and also have endometriosis and am 7 weeks post-hysterectomy for adenomyosis, which has caused a flare of my Fibro. I found Oxycontin to cause a great deal of fatigue. The longer I took it, the worse it got. Even on a small dosage, my body wanted more at smaller intervals and sleep was the only way to get through the time. It was awful. I am on MS Contin now. It is still a time released Morphine drug, but I can take less of it to achieve the same pain relief. I don't feel tired or fatigued and I don't feel the need to take more at earlier time intervals. I started taking 30 mgs every 8 hrs, then went to 30 mgs 12. Things got better for a short period and I was down to 15 mg every 12 hours, but since I started physcial therapy, I am back up to 30 mg every 12 hours until I work through the pain. Just a thought; I think it works much, much better than Oxy! Ask your doctor about switching to this. Good Luck.