Hi dear,
Based on the symptoms you have mentioned in your question, from the way you describe it, it might sound like
lymphoma but i highly doubt it.. The main reason i doubt that is because you said the swelling on the lymph node comes and goes, however people with lymphoma the swelling stays or gets worse as time goes by.
The swollen lymph node that you have is possibly just due to infection, an
upper respiratory infection. it would be very helpful if you could include in your question the time lapse of your condition so i could suggest you treatment options you can follow.
I also suspect the reason for your
difficulty breathing, feeling hot and sleep problems is due to
anxiety, try to calm yourself down and don't worry much..
At the moment i suggest you to wait for few more days and see if your symptoms is getting better, if not then visit a Doctor, to evaluate your condition and run the appropriate tests.
So don't worry and relax, i'm sure you will be just fine ..
Wishing you all the best.