She ised to burp every ounce..but lately,like withon the last week she hasnt been wanting to burp. She drinks 3oz every 3hours and she can drink the whole bottle and not burp once!! I try and try to burp her but it neber comes out. I stretch her and the put her in a ball and stretch....and etc...i pat her back and rub it and all and its not cutting it. Sometimes she burps one time every bottle but not every bottle. Is that normal?? Could it be her new formula? The health dept. Just switched her from gerber good start to gerber gentle about a week or two ago because she was constipated too much.