I have had Sarcoidosis when I was in my mid 30s(66 now) Sarcoidosis is an auto-imune disease that has varying symptoms and looks a lot like HIV. I lost a lot of weight went from 180 to 120ish...night sweats, fatigue(was unable to work. My blood counts where always way outside of the norm. Spent months I'm hospital on AIDS floor try to get a diagnosis
Turns out my auto-imune system was over active and trying to killme (it almost succeeded a couple time during ambulance ride to hospital). I was treated with Prednisone which did the trick for me...that is another story though.
Have fun and good luck out there!