Nausea and Dizziness and Vomiting?

My moms very sick, she is extremely Dizzy and vomited once, She has a hiatial hernia but she doesn't think that was it. she ate 1 McDonald Cheeseburger and a Muffin today, (Please don't say "THAT'S WHAT YOU GET FOR EATING MCDONALDS" Because that's not helpful.) I feel really bad for her, also she had a headache. She doesn't think its her ears, or anything like that. She needed help getting to the bathroom, that's how dizzy she was! Could it just be the flu because she was at the hospital? or do you think its something else :/