I am desperate for some insight!

I am 28. About 2 months ago I began experiencing low grade fevers, night sweats, pressure in my left side, headaches, knee and hip pain, severe fatigue and muscle spasms. Until that point, I have been quite healthy. I have had 2 trips to the E.R., and countless trips to my P.A., ( who treats me as if it's all in my head, ops: nevermind that I am famous for my excuses NOT to go to the doctor!) My life has changed drastically, yet no one seems to know what's wrong- I am very tired and feeling short of hope! I am scheduled for a visit with a rheumatologist- in THREE months! My P.A. says that it can't be Lupus because my ANA ( ran once) was negative. I am not so sure.

If anyone has any insight, please reply! Thanks for your time!