Lactose Intolerance Poop?!

Am

My 7 week old has suffered with reflux since birth so is in Anti Reflux milk. She seemed in so much pain with acid and wind that I decided to put her on Infacol which she’s had for about 5 weeks.

But I’m now concerned about her poop and wonder if she is lactose intolerant which is causing her all these issues.

I started Colief a few weeks ago but it’s not made any difference. At her last weigh in she hadn’t put on as much as they would like so has to be weighed again next week.

I read that frothy poop can be a sign of lactose intolerance which is what she has.

Feel so sorry for her and wondered if anyone else has experience of this?!