weight loss, muscle weakness, No muscle pain or atrophy. no ataxia.

There are many diseases that can do that. A lot would depend on the lifestyle you live and obviously your body. Some disease would be hepatitis or mononucleosis. Your best bet would be to get a blood test which should tell you what the problem is. I hope all is well in the end.

Could be anything, from mononucleosis ("mono") to diabetes to cancer.
Voice your concerns with a medical doctor. Good luck!

AIDS

How is your blood sugar? Are you overly tired, overly thirsty? You could be diabetic.

AIDS

M.S

SOUNDS LIKE HIV

Mono for one. Anorexia for another.

Don't know except maybe depression. That's a big maybe. Go to the doctor and find out so they can fix what ever is wrong early on.

arthiritis?

could be MS

anerexia

Could be several things. Sounds like neurological or neuromuscular problem. Or, could be a nutritional deficit. Only a Dr. should diagnose this. So, see one soon!