Affects of formula - poo, farts and sick?

[Maisieskates]

DD is 5.5mths and was ebf until about 3 weeks ago. For the past 3 weeks I've slowly been introducing formula (Aptamil 1). She has 5 feeds a day - 3 are currently breast milk, 1 is formula and 1 a mix of expressed and formula. I wind her after (and sometimes during) each feed and there is normally a large satisfying burp.

My plan is to get her on 4 formula feeds plus 1 breast feed - hopefully in 3 weeks time.

Since introducing formula 3 things have happened:

1 Her poo has changed consistency and she normally now only has one a day. I am not worried about this.
2 She'll fart much more often - both when being fed and when not feeding. This seems to cause her some discomfort, especially when feeding so I'm quite concerned about this.
3 She likes to play on her belly and is often sick when she does. I'm really worried about this.

Is the above normal when introducing formula? Will it calm down? Should I switch formula brand? Any suggestions much appreciated.

My ds didn't do well on Aptamil, we had constant runny poos. We switched to SMA and he was fine. While you shouldn't chop and change formulas all the time, you're wise to change if your baby doesn't seem to tolerate one brand well. They do need time to adjust to a new formula, that can take a week or two.

If you do switch, do it gradually, say two thirds Aptamil one third new formula for a day or two, then half and half, then all new formula after a couple of days.