Poppy Pony Has a Problem

Today, Poppy suddenly developed diarrhea. Pretty gross. I washed her (an experience I don't care to repeat) and then I ran to the web and started searching. Which freaked me out. According to my research, it's extremely common for foals this age to develop something called foal-heat diarrhea, so called because it's onset is at the time of the mother mare's first heat cycle after giving birth. If this is what it is, it's self-limiting and no big deal.

If that isn't what it is, it could be any of a number of other things, many of which are rapidly fatal. 

By the time the foal starts to look sick, it's often too late.

I'm calling the vet ASAP in the morning. I'd be totally devastated if something happened to Poppy. We are all head over heels in love with her.