Hold your horses folks.
Diarrhea is the bodies way of getting rid of offending bacterium, or is a sign of parsites, etc. - the last thing you want to do is stop the process by using Immodium. That would be like putting a plug in a festering abscess.
My suggestions are:
-fast for 12-24 hours to give the gut time to rest - that means NO food, water only
-slowly introduce small amounts of bland diet throughout the day. Boiled ground meats and rice (do not boil the rice in the meat juice which is where all the fat goes), cottage cheese, scrambled egg (no butter, cheese or milk added to it), or commerical diets such as Hills I/D
-continue bland diet for 2-3 days. Then slowly reintroduce normal diet. 75% bland to 25% regular for the 1st day, then 50/50 then 25/75 then back to normal
if no improvement I would suggest treating for parasites even if negative fecal. Metronidazole and/or Panacur should be sufficient -you can even do this now, imperically, if you do not want to wait and see any longer
if no improvement on meds and diet change - you need to test for further diagnostics (EPI, PLI issues, etc.)