Yea I'm sorry to say it is very normal and even an older child will wake up during the night if they are not feeling well.
About the diahorrea bug, your Doc may advise you to feed at nights short-term to keep his fluids up. But you will need to watch if it is becoming a habit like Deb said
Also I don't know his sleeping preference but sleeping on his tummy may be more relaxing for his intenstines and he may therefore sleep better that way.