Dont think there is any medication for such young infant. If baby is breastfeeding, take 1000mg of Vit C and try to feed baby often. Put humidifier or diffuse high quality essential oils (if you are comfortable with it). The above is what works for me.
After you get well, remember never ever kiss baby face. I know it is hard to resist but in order to not pass any flu or cough virus to your baby, we have to control ourselves, you can kiss their belly but refrain from the face.