Adding cereal to formula?

My 5 week old daughter is fed anywhere from 2-3 oz every 1.5-2.5 hours. She does seem satisfied after eating but about 30 mins to an hour after eating she is crying a lot and seems like she's in pain. I've tried adding gas drops to her formula, switching her formula, and using gripe water. The only thing that seems to help (temporarily) is the gripe water. The consistent advice I seem to be getting from other moms is to add a small amount of cereal to her formula. They said it sounds like she has reflux and the cereal could help. Has anyone heard of this?