What Causes Persistent Fatigue And Body Ache After Hysterectomy?

i am a 39 yr old. Been diagnosed with endometriosis. Had hysterectomy a yr ago. Do not have the severe pelvic pain, but do still have achiness, swelling, fatigue, about two weeks out of every month. Thought all this would subside with the surgery. Feels like you have the flu bad.. aches to the bones..