I don’t think your friend have to go to an ER because of viral gastroenteritis. Unless she was suffering from dehydration, there’s no specific treatment for it. I would advise against drinks with a high sugar content, clear soups (like bouillon) that are salty and caffeinated drinks.

“but I spent the night at her house last night. Which now I think wasn’t the best idea.” — Uh…you think? Oh well, we all make mistakes.

“if you know what some stomach virus symptoms are please answer. I want to know if I have it” — the primary symptoms are vomiting and watery diarrhea. there are different viruses that cause gastroenteritis and these can produce some variation in symptoms. with Rotavirus — vomiting, watery diarrhea, fever & abdominal pain. Rotavirus infection are pretty common Nov. – Apr. with Adenovirus — Diarrhea & vomiting. with Caliciviruses like Norovirus — vomiting and diarrhea, fatigue, headache, and sometimes muscle aches and these are common Oct.- Apr. And with Astrovirus — there’s vomiting & diarrhea and it’s most active during winter.

I put my money on a Norovirus infection. I think this is the virus causing your friend’s gastroenteritis. It’s the leading cause in all ages, the most common cause, is responsible for most epidemics and occurs more frequently during the months from October to April. And the incubation period after exposure is from 1 to 3 days.

“I’m sorry I didn’t really give a lot of details…” — That’s okay, none needed.