It is normal that the child gets sick at the first a few weeks of him/her childcare time, because he/she has more opportunities to contact various viruses than staying at home. It will be much better when he/she is used to the new environment after a few weeks.
I remembed that my child immidiately got a high temperature after staying the childcare only for an half day this first time, but he never got any sick from zero to one and half years old before going to childcare.