Tucker is sick. Need advice.

[My Tucker Boy]

Tucker was up all night last night and had me up with him because he had an upset tummy and diarrhea. He had about 3 or 4 bad runny poops between 1:30am and 11:00 am this morning. I called the vet and they told me to get childrens immodium and give him half of a childrens dose. I did that and he did not poop any more today till about 10 minutes ago at 9:00pm. Again it was runny diarrhea. Does anybody know if I can give him more of the immodium or how often you can give something like that? About an hour ago he was sitting in my lap and started making noises like he was going to throw up but he didnt. He is whining a bit when he crawls up in my lap like he is trying to tell me he doesnt feel good. My husband thinks I am crazy for acting like the dog talks to me but I just tell him to be quiet. Tucker is my baby and he just doesnt get it. He is concerned about him too though.
Any suggestions?

[JeanieK]

I would give it to him however frequent it says you can give it to a child.