THANK YOU GUYS--- I got home tonite, let Miriam swim and soak in warm water, and then very gently felt long her vent area... I felt something really hard... so with a warm, damp paper towel I gently massaged and lightly pushed and THIS came out, followed by loads of poops:
The poop that followed was mucous-y and very smelly. Also, she has some tissue protruding from her vent area now, which I assume is from the irritation/swelling?? She seems ok; she went back to her tank and proceeded to check around for a meal! I will bring the stone to the vet tomorrow night, and have him check her over very carefully.
She HAS to feel better with that gone... but I still felt a smaller hardness further up, but did not want to push anymore on her. Geez, she's so tiny, I feel like I could crush her, you know??
Ideas on what this is, and why... think she got dehydrated when she was ill??