I just bought these yesterday for DD and it seems that while she is drinking, there are SO many air bubbles in the bottle and nipple. I'm using the 4oz bottles which come with the level 1 slow-flow nipple. DD is 17 days old. I'm assuming that these air bubbles should not be there and are creating gas, but for all I know they are supposed to be there and are the bottle's "anti-colic" system working. Can anyone offer any advice?