Dear Carm -
The symptoms you described may be a part of Chronic Fatigue Syndrome (CFS). CFS symptoms may include recurring sore throats or swollen glands, muscle or joint pain, headaches, flu-like aches and/or feverish feeling, sleep problems, and/or exercise intolerance (sudden, severe worsening of symptoms within hours or days after exercise or other exertion). In fact, exercise intolerance is a unique, defining characteristic of CFS.
If you have some of these symptoms and think that CFS is a possibility, you might want to try the Do I Have CFS? self-assessment at the CFIDS Association website (CFIDS is another name for CFS). Here's the link:
Fatigue or exhaustion is a very common symptom that can be caused by a wide variety of different sources, including anemia, MS, lupus, and many other conditions. A swollen lymph node is usually a sign of infection. Whether or not CFS seems to fit your symptoms, you should see your doctor. Describe ALL new or recurring symptoms. Your doctor should test you for a variety of conditions that can cause fatigue and for a wide variety of infections. Here's a list, provided by the CFIDS Association:
There is no test (yet) to confirm CFS, but if your symptoms fit the CFS definition and all of your other tests are negative, then your doctor may diagnose you based on your symptoms.
Fatigue is such a common and varied symptom of so many conditions that it can be difficult to find the cause. Don't give up! If your doctor isn't willing to work with you to get to the bottom of your symptoms, then find another. Something has changed for you, and there is a medical explanation, but it may take a lot of persistence to find it so that you can start treating the underlying cause.
Good luck. If you have other questions about CFS in particular, please feel free to ask me, either through this site or by visiting my blog at www.livewithcfs.blogspot.com.