11 & 1/2 month has a tummy bug...?

Hi, my son has a bug that started today around 2pm its been around 7hours....he has vomited and had diarrhea. How long does it last for? My son was screaming cause he was so tired and wanted his milk and would not sleep without it so I gave him around 120 mls so he could sleep,also giving him fluids.....will he be sicker with the milk? How soon after they eat or drink do they throw up.......