Ftm with questions?!? Help

So my daughter is 6 weeks old today. Took her to her one month appointment two weeks ago she weighs 7lbs 13oz took her to the doctor on Thursday she weighed 7lbs 14oz she has been throwing up a lot which I expressed to her doctors a few weeks back. So I changed her formula from Similac advance which she was constantly throwing up. I changed it to nutrimugen by enfamil and she loves it. No more crying no more throwing up finally. My doctor also said to add rice to her milk has anyone tried this and it helped with weight and reflux? Or should I try just the milk and see if that will help her gain weight?!?