Breastfed babies sometimes don't poop more than a couple times a day, so I wouldn't necessarily worry about that. And the cold can throw off EVERYTHING (poor little guy!).
How is the latch, BTW? If he's not latching quite well enough, he could be swallowing too much air, which can give him more gas. Any chance you could get it checked, just to make sure? Is he gaining weight well and having lots of wet diapers (even if not poopy ones)? Finally, have you tried doing a lot of bicycles with his legs to get the gas out? I found that and tummy massage helped.