ginger is correct, she is either constipated or obstructed and needs to be seen by a doctor especially at this point.
Could she possibly have ate something that may have obstructed her,If not then Canned pumpkin can really help .Give her about a teaspoon and then go from there.It really helps with going to the bathroom.Also you can freeze some and give it to her as a frozen treat.It is natural and safe.
Take her to the vet straight away. Either today (I am not sure what time it is now where you live) or first thing in the morning. This is not right.
This could be constipation, or it could possibly be some kind of intestinal blockage.
I would say that if she has any other symptoms, such as : vomiting, or attempting to vomit, or retching/ lethargy / shaking, or shivering / 'hunching' her back with her tail between her legs / sleeping a lot and not wanting to get up.....then take her to the ER vet as soon as possible.
Even if it's just constipation, she will need some prescribed laxative. But she will need a thorough assessment first, to make sure laxatives are appropriate. In some cases, administration of laxatives could be dangerous, so it's wise to get the vet's advice.