5 year old daughter and chicken pox.....?

Woke up this Morning and my little girl was getting ready for school when i noticed some spots on her tummy and thighs some on her ankles and arms.....took her to the dr and he said it was too early to tell if it was chicken pox but theres a possibility?????how do i know for sure if its chicken pox??? Also I have a 1 year old son and im so worried he does not get them....was supposed to have his vaccination this week but has had tonsillitis.....help advise needed.