Based on the tests you have had done it appears that you have no detectable abnormality and yet you have symptoms which impact on your ability to function. This is frustrating, both for the patient and the physician. You could well have chronic fatigue syndrome or fibromyalgia. There is no test, which can prove the diagnosis. The diagnosis is made purely based on the patient's history and physical findings and the absence of any other disease, which could cause the symptoms you mention. Some of the criteria for chronic fatigue syndrome include:
1. Problems with short-term memory and concentration
2. Sore throat
3. Tender lymph nodes
4. Muscle ache
5. Joint pain without swelling
6. Non-fresh sleep
7. On and off headaches
8. Marked fatigue after exercise lasting > 24 hours
No single medication has been found to be effective but many physicians give a trial of an antidepressant initially even if you are not depressed). Other treatment regimens include antivirals and corticosteroids. My suggestion is you see a physician who treats chronic fatigue and get his opinion