First, if she is having unproductive retching (dry-heaving) and her abdomen is distended and hard, you need to take her to a veterinarian immediately. If that is not the case, there are several things that could be wrong with her:
1) She could have pancreatitis, in which case she would need bloodwork from your vet to confirm it, and would likely need hospitalization. Fatty table scraps can cause this, but it can be caused by other things, too.
2) She could have a foreign body obstructing her intestines or stomach, and would need xrays from your vet to diagnose this, and then possible surgery.
3) She could have gastroenteritis, which is inflammation of the gastrointestinal tract from an unknown cause.
4) She could have organ dysfunction, which would require bloodwork to diagnose and then potential hospitalization.
5) She could have intestinal parasites, which would need to be diagnosed by a fecal sample.
She is most likely uncomfortable right now. The best thing for her would be to see your veterinarian to find out what is wrong with her. In the meantime, however, you can try this. Do not give her ANY food or water until late tonight. At that time, if she has not vomited, you may offer her a small amount of water. If she holds that down, you may offer a small amount of a bland diet of boiled chick breast and white rice in a 50/50 mixture. If she holds that down, you may feed this diet in 4-5 small meals throughout the day tomorrow and the following day, and then if all goes well, you may switch back to her regular diet on the 3rd day. If she continues to vomit, however, you should take her to see your vet.