Working night shifts....advice plz

So I rotate between night and day shift..however I haven't had to do any nights luckily for almost 2 whole months. Well my luck ended and the past two nights I've had to work 7 pm to 7:30 am. I keep getting sick through out the night (puking and diarrhea) and this happened a few months ago during night shifts as well. Why isn't my body cooperating? I haven't eaten any big meals because I knew it'd make it worse but I've been drinking water and snacking lightly throughout the night but I'm still so sick and feel almost drunk by the time I get off work. I don't get what's going on..it's literally only when I work night shifts..anyone have any thoughts or advice? Thanks in advance...