Thanks for writing in,
Sorry to hear that your girl sounds so uncomfortable. What you can do is give her about 1 tablespoon per 20 pound of regular canned pumpkin on her food. THis will act as a bulk laxative to help things move along. If by tomorrow she is continuing to strain then you should definltey take her to your vet to ensure there isn't some sort of blockage. I hope this helps!
Veterinarian
Doctor of Veterinary Medicine