Thank you so much for what you guys wrote! Missy sends pupppy kisses to all of you!!
Missy and I just got home. The vet says she has a stomach infection.
She's on anti-biotics. The vet didn't find any parasites, but she put her on a dewormer, just in case. If there's no more runny or bloody poop by tomorrow, she won't have to be hospitalized. At this point, they're worried she might get dehydrated and have to put her on an IV.
She's in good spirits though! She got home, ate and dranks lots of water. Now she wants to play. All good signs. Keep your fingers crossed that she won't have to be hospitalized!!!!!