What Could Be Wrong With Me. I Am Female 44

What could be wrong with me. I am female 44 and have been loosing weight for 3 1\2 years (145 lbs lost) I am 129 now I have no appetite terrible night sweats low grade fever99.4 thinning of hair fatigue leg aches. I have seen my doctor and he tested thyroid it is good.a cortisol blood test for Addison's disease it was good. Blood test look good except for slight elevated white blood cell count. Vitamin D was good.colonoscopy and endoscopy both looked great and ultrasound of ovaries and uteris looked good. I want to feel better but can't find answers :(