Hi. I Have A 2 Year Old That I Recently

Hi. I have a 2 year old that I recently brought to the Pediatrician for high fever. She was tested and has the flu. A couple days later I noticed her gums were very swollen and bleeding. I brought her to the dentist and they just said that she has some sort of virus and that it has to just run its course. Is the flu and this virus somehow tied together? She is unable to eat anything and she now hardly even drinks water when she loved drinking at the very least. I'm just very concerned for her. I noticed today that she has a small pimple like bump on her lip. Nobody in our household has any history of herpes or anything.
Thank you