What could be causing enlarged lymph nodes for the past 9 months?

[Carolvds]

I am a 43 year old female and have been battling to get a diagnosis for what could be wrong with me for the past 9 months. I go through periods of feeling better but at some time am so fatigued and achy it is difficult to get out of bed.

I have slightly enlarged lymph nodes (most are pea sized) in my chest area, neck, collar bone, under arm and groin. I have had a chest X-ray and CT scan which have revealed these enlarged lymph nodes but nothing else.

A routine mammogram in August last year revealed a2cm enlarged lymph nodes under my left arm. This was biopsied (fine needle and true cut) and revealed granumalatous inflammation and reactive lymph nodes so I was admitted to hospital as they were worried that it could be TB. They conducted various tests including a lumbar puncture but I tested negative for everything including TB and meningitis. All the other tests conducted also came back negative however I first had an inconclusive and a false positive result on a HIV test.

They said that they did not want to biopsy any of the lymph nodes in my chest or neck area as they were all in quite difficult places and would involve major surgery.  

Over the past few months I have been backwards and forwards to hospital but still no progress on a diagnosis.

My general symptoms are enlarged lymph nodes which get more inflamed if I overdo things, dreadful soaking night sweats, weight loss (I lost 30kgs but this has stabilized now), constant tinnitus and extreme fatigue. I have recently been taking my temperature throughout the day and this ranges between 35.3 and 38.2.

At one stage the doctors seemed to think it could be lymphoma then they seemed to be leaning towards sarcoidosis, now they are rechecking again for the Epstein Barr virus (I did have glandular fever as a teenager and again in my thirties). They have checked my hormones and everything appears to be fine there plus I am still on my usual cycle, etc. Thyroid test also came back normal. The only thing that was slightly abnormal was my white blood cell count which was apparently elevated.

Has anyone got any ideas of a possible diagnosis or how I can get to a diagnosis? My sister had breast cancer and she had to have chemo, etc, plus a double mastectomy and I am a bit worried about the delay in getting a diagnosis.