I had the stomach flu for three days, and I barely ate anything. I didn't physically vomit, but I had major body aches, headache, and low-grade fever (99.8). After the third day, I woke up with swollen gums, which are painful and uncomfortable, and so far, they have lasted three days. It's very difficult to eat because of the discomfort. What could be causing the swollen gums, and what do you suggest I do in order to treat the condition/