The last time I ate at McDonald's, I ended up with projectile vomiting that lasted for three days. It was from McDonald's too as it was the only thing I had eaten that day and the previous that had the potential for contamination. (I was a poor student at the time and often skipped meals.) It is amazing how much strength your body can exert to empty your stomach quickly.
For starters, you'd probably had a crappy diet being a poor student and skipping meals. I doubt McD's had anything to do with your reflux apart from the fact it was food. And I know it's hyperbole, but if you're projectile vomiting for 3 days, you need to go to hospital.
"Spock, did you see the looks on their faces?" "Yes, Captain, a sort of vacant contentment."