A couole days ago my baby was geting wildly fustrated with her bottles we have been using since birth. She wasnt finishing them and screaming and fighting the bottle. Im thinking it was cause the flow was to slow and she was getting fustrated. I switched to the little avent bottle i got with my amazon baby registry(not sure the nipple size) but i knew it was faster(she used to choke on this one when she was a newborn) she is 7 weeks now. She was doing just fine for days chugging down her formula. I burp every few minutes and keep her uoright for at least 10 mins after feedings. But today she is back to soitting uo on some feedings and vomiting on ither feedings. My last option is a playtex ventair i have. Should i try this. She is always very gassy. She even will be trying to push out gas while sucking a bottle. Which is wildly fustrating. Helppppppppp