Stomach Flu or Food Poisoning?

I can't figure it out!

On Sunday night, my girlfriend went over to her father's house and ate a couple slices of Papa Murphy's pizza that had been sitting out since about noon. It was around 11:00 pm when she ate them. The next morning at around 9:30 am she texted me, complaining of chills, aches, nausea and a headache. To me, it sounded like a bug, but came on in the appropriate time that food poisoning would occur. I also know that some people can experience fever and aches with food poisoning. So, I went over to her house to care for her, wearing a mouth mask most of the time (I can be a little neurotic) and washed and sanitized my hands almost every thirty minutes or more. I also didn't kiss or hug her. However, I did take my mask off a few times while we were in the same room. I sanitized all of her surfaces, bathrooms, railings and places she had been with medical wipes. She had a small bout of vomiting, with diarrhea throughout that day and today is feeling better. I can't tell if it was a bug or food illness. It's important to me, seeing as I am very...emetophobic...very...and am freaking out wondering if I'll get it or not. I saw her Saturday, but not Sunday, half the day on Monday while I cared for her, and not today. I'm hoping with all of my effort, if she was contagious, I won't get it. But, I was wondering to any of you, what you all think it was, and what my chances are that I will get sick. Thanks so much.