Yoiu can ask but the parent will likely be very upset and especially if there are no grandparents to help out. This is one of the downsides to daycare for sure. Good news is after the first couple of years you build up a greater immunity and no longer catch everything going around. Be prepared to have the parents protest and start looking for another caregiver. Unless you are so sick you are likely to fall asleep when you should be watching he kids then unfortunately that is just what happens in home daycare that you are there and struggle through as the parents are counting on you to be available and some will become so ticked off they look for someone more reliable. Since this is your first time closing it might go over better but not likely. The good news is that there is a long weekend coming up if you can hang in for that. A cold just has to run it's course - about 14 days of acute phase and another week of recovery. And yes that makes it just about time to catch the next cold.