Hi all my daughter is 3 weeks 3 days im using phillips avent natural bottles she had the 0+ teets but kept falling asleep on her feeds ive changed today to the 1 month + teets and a few times seems like she is gagging on bottle she has been fussy with her feeding all day since the change taking 2/3 ounces during the day then her usual 4 ouces this evening. Just done her midnight feed and she onky taken 2 not sure if i should change the teets back?