Sick baby

I have a 10 month old and he has had a very high temp for 3 days now. He has had an ear infection and has been on meds. He has been super lethargic and not eating well. We went to the ER last night for 104.8. They checked for RSV and the flu and they came up negative. They basically just sent us home.

I’m just concerned because he is usually a very active baby and always eats sooooo much.

Should I be concerned? Could there be something else going on?