My DD just turned 7 weeks yesterday - I would say she was about the same as the 1.5 - 3 hours in the day and then a couple of longer stretches at night around 6 weeks, but she has been eating MUCH more lately - I am thinking it is just a growth spurt (been feeding every 1 - 2 hours during the day and every 2 or so at night...makes for a long day!)
Re: How long does your BF six week old
During the day, usually about 3 hours (and sometimes I wake her with a diaper change to keep her from napping through that during the day)
Though the past two days, she's thrown in a couple 1.5/ 2 hr feedings, I suspect a growth spurt.
At night, she'll start with a 5 hour stretch, then usually gets back on three hours.
This sounds like my LO as well, except he goes a 5-6 hr stretch at night, then 2-3 hours.