Small breed are known for throwing up stomach bile in the am due to a reaction to having an empty stomach.
The only suggestion that I can give you would be to start giving her an additional meal later in the evening. that way she has some substance to get her through the night. So that she doesn't get to overweight just portion her reg. amount into three instead of two meals.
If that doesn't work you may want to contact your family vet who knows her best and would be better at answering your concerns.
__________________ Mommy to: Quincy, & Ruby Bella / Miah & Brandi Gone but Never Forgotten |