Doctor her food with cottage cheese, hamburger, chicken broth low salt
a little broth of veggies you cook....and feed her small amounts..
Several of mine do it and they always go a week then pick back up...They may vomit because they have indigestion and ate grass..watch her carefully and examine her bowel and her vomit...log what you see in it..
water is important..
I also add from this time of your date forward a can of PUPPY well known brand...with Choline., per my vets instructions,,,,till birth as they need the extra choline and it is found in puppy food..
Other than adding a bit of extra virgin olive oil to the food and a little powder milk on the top of food,...they will eat when they feel better....today . or tomorrow but you must only feed small amounts and see if what you add helps...Adding a meat broth , first helps entice them..
Humans are PICKY when pg also.