Hi, I' M Wondering Why Does My Stomache Hurt After

Hi, I' m wondering why does my stomache hurt after consuming fried potatoes? This has happened before I went to the same restaurant and I came home with an upset stomach within hours after eating. I had to use the bathroom, pass stool, was feeling nausea, and feeling like my body temp went up feverish/ sweating and on top of that my heartbeat went up. After using the restroom I felt slightly better but my stomachs is still in motion I could say and I feel awful. I asked the restaurant what they use to fry their fries in and they said it's sunflower oil and this is the only thing I ate both times.
This happened once years ago after eating fried food at a Chinese restaurant and I was in severe pain,sweating, bathroom runs when I got home, I thought it was just the food. But could I have a problem with sunflower oil? Thanks in advance Kiki