Sounds to me like she may have a really bad case of giardia or other worm infestation. But the only one who will be able to tell you for sure is your vet. Maybe take her to a "real" vet if you are uncomfortable with the newbie one at your low cost clinic.
Assumptions do nothing but make an ass out of u and me.
We can stick our heads in the sand for only so long before it starts choking us. Face it folks. The pet population is bad ALL OVER THE WORLD!