5 year old boy - heath help!

I’m looking for some advice desperately. My five year old boy has in recent months had random episodes of sickness, as well as multiple ear infections where he vomits. He seems to get alot of infections.

He was nauseous Friday morning, sick yesterday morning and sick again this morning / afternoon. I had him checked at the pharmacy and he has an ear infection. Aside from this, since summer he’s lost weight, he’s dark around the eyes and is paler. He has doctors this week and is on antibiotics for the ear infection but I can’t help but worry there is something more sinister because of the morning nausea / vomiting in the morning (I know it isn’t a bug), I’m reading the worst online and it says it can be a brain T. Am I over thinking this?