Don't feed him eggs if he's loose, with mine it makes things 100 times worse
Personally I'd get him back to the vet before thursday, it must be making him feel really crap
THe prokolin should kick in by tomorrow, he'll seem much better, but remember, it most probably isn't the cure you're looking for, it's just working on the symptom not the cause.
Have you tried giving him some mashed up banana ans some natural yoghurt? That's givig him both pro and pre biotics.. Slippery elm powder also works well on a lot of dogs.