Need some help please!

No censoring

My husband and I had a couple over for dinner tonight. After about 30 minutes, the girl went to the bathroom and threw up. And then within 30 min/45 min she threw up three times. She says she was fine and it came on really suddenly and thinks it was the subway she ate earlier but they left just in case. I feel like it probably was food poisoning with how fast it came on but reassure me that it was and not a stomach bug? She was acting fine and even tried eating a bit of food.