Hey Abz, hope you don't mind my butting in.
I know you're far more of a veteran than I am but both when I first started and now, after the week of break I had the very-sick-for-a-day-or-two episode as well. Maybe it's our body's way of rebelling. Personally I've first hatched plans to not let anyone see I have it -my mom and mister would have insisted I get on drugs and food with them if they did- and then ignored it for long enough that it left me around day 5 or 6 so I hope yours does the same thing!