Please help, Puppy barfing!?

3 weeks ago Abby my lab puppy started barfing, I took her to the vet after five days of her not keeping anything down, and he wasn't worried since she didn't have diarrhea and she was still active and playful. He said i was overfeeding her but i don't think so because she had been eating that amount of food for about 2 1/2 weeks before she stared barfing. A couple days later i stared her on a yogurt and rice diet and that helped her out and she started holding down her food even her pedigree puppy chow. After a few days of her holding down her food the humane society had an opening for a spading i had to take it. That was a week ago. Yesterday she barfed once and today she has barfed 5 times already. I am worried because she lost a couple of pounds when she barfing last time and still is skinny. And she is still is really hungry and has been for a few days. I think i am going to ask another local vet tomorrow if they are open i thought i would ask here tonight so can anyone please help!!