My throat only started to get sore this afternoon.my baby has sinusitis did she infect me?

Hard to guess: If symptoms are very mild, people usually wait a day or two. Throat pain can be from a strep throat infection (antibiotics are needed), a cold or flu (Tamiflu may be needed), or from some other cause such as allergies or irritants. Usually, a person sees the doctor if the sore throat is bothersome, recurrent, or doesn't go away in a day or two (sooner if the flu is suspected and needs treatment).