Glad to read the good news!
It could very well have been a reaction to the vaccine. I had one a few years ago who was given a combo + Lepto at 10 wks despite my advice to wait on the Lepto. BAD diarrhea! The vaccine manufacturer agreed it was likely vaccine shock basically.
But, this is why I give Neopar at 5 wks and my first combo at 7-7.5 wks myself. I have protection built by the time I have to go in for well checks and w/ my work, it's pretty hard to avoid walking thru the stuff at some of the places w/ all the strays wandering around. Puppies at dew claw age SHOULD have AMPLE immunity against parvo, etc, btw. Just keep them warm (since they are lacking that ability to regulate body temp) and you should be fine.