Congratulations on the new baby. Adjusting to the new home can be stressful and affect eating. I'd stick to whatever the breeder was feeding and only if she completely refuses to eat then supplement with some "enticement" goodies like a little boiled chicken breast (no skin or fat), or a bit of cottage cheese on top of her regular food.
For either diarrhea or constipation, it is often recommended here that you give a little cooked canned pumpkin (with NO spices or added stuff). Sometimes you can get them to eat it off your finger.
Any changes in food must be made very slowly over a period of 2 weeks or so.
Good luck, and show us some pictures of the wee one when you can
