Sudden onset of sickness

I haven't been sick in years so I don't know what the norm is.

Last night I was perfectly fine after dinner, started to feel a bit sick after dessert (just plain ice cream) but then come about 23:00, I was just insanely sick. I threw up multiple times in the night, my issues migrated South of you know what I mean, and I have NO clue what could have caused this. I didn't eat anything unusual last night, the night before I went out with a coworker but we had the exact same thing and she's fine.

Is it normal for a sickness to hit you so suddenly?

NB, pregnancy is not a possibility here. Unexplained infertility and only about 4/5dpp.