Hello, I'm Dr. Deb.
I recently came online and see that your question hasn't been answered. I'm so sorry that you've had to wait for a response, but if you still need assistance, I'd like to help if I can.
I'm so sorry that you lost your cat's kitten; I know how terribly sad this is when it happens:(
I have several thoughts as to why your female cat may not be eating;
1. She could be running a mild fever which is commonly seen about 1 day after delivery and would be considered normal. The fever doesn't last long, though, so her appetite should return within 12 hours or so.
2. She could have developed an infection (metritis) which can also cause a fever and disinterest in eating.
3. There are other causes for a fever in a cat such as Fever of Unknown Origin (which is exactly what it sounds like) but are lower on the list.
4. It seems unlikely that pancreatitis would develop but this condition can suddenly develop and cause the patient to lose interest in food (we think these cats are painful which is why they don't want to eat).
If you have access to a thermometer, it might be helpful to take her temperature although this isn't always the easiest thing to do in a cat. Normal is between 100 and 102.5. If it's high, then I might monitor her for several more hours as long as she's otherwise acting her normal self.
But if the fever persists (if she has one) and/or her disinterest in food for more than 24 hours, then a vet visit might be prudent.
I hope this helps although, again, my apologies for the delayed reply. Deb