Severe pain in all joints

Several months ago I saw my dr. about swelling,knots,and severe pain in my knuckles. He done some blood work and my wbc was low. He had no explanation for why my fingers hurt so badly. He said that if it spread to let him know.
Since then I'm having occasional pain in my neck,chest,back,hips and legs.The pain is so severe and no pain medication (tylenol,Ibuprofen 800 mg.,Tramadol 50 mg.) has helped.
I'm tired all the time (simple tasks are a major issue for me on a bad day).I have difficulty sleeping due to the pain,and when I do go to sleep sometimes I have difficulty getting out of bed(the simple motions of getting up or sitting back down causes excrusiating pain).
I stay sick all the time.Anything that goes around,I catch. I'm sick as I type, with every symptom of the flu.But the ER Dr. found only that my wbc is low no xrays or other tests were done though.
My menstrual period stopped about 2 months ago and I'm moody and easily irritated these days which is soooo unlike me.
I'm only 40 years old and feel as though my body is falling apart,because I've always been so active and can no longer do the things I did just 2 years ago.
Do you have any suggetions. I'm really afraid because my Grandfather had RA which crippled him. Could this be an issue for me as well.
Please help. I'm literally in tears.

Thanx in advance for all your help and suggestions.

Sincerely,
Angela Stricklin