What does this mean?

I was about to go to sleep then I got this "You start feeling nauseous, but it passes after some time." I have advanced science grade so I checked the extra stats and it says I'm on my 2 day of the cycle, not pregnant, not intended to. So does someone know what this means? Is it the same from when you have period cramps and the game says "you are having strong stomach cramping." Or something like that...