I Had A Fever For 2 Days, And The Lymph

I had a fever for 2 days, and the lymph nodes on my neck are hard and swollen. About 2 days after the fever, I developed sores in my mouth and my gums are all red and swollen and bleeding. I know the gums aren't related to gingivitis because I went to the dentist less than a month ago and he said my teeth and gums are in great shape. I'm very worried about the bleeding gums. They hurt so bad that I can't eat. I've lost over ten pounds.