My daughter will be 5 weeks old on Monday and last night she slept from 10pm to 6:45am!! I woke up a couple times during that stretch panicked that something was wrong but she was just snoozing away. She did do terrible with napping yesterday so I guess she was just exhausted from that. I don't know if you are supposed to let them sleep so long at this age but man it felt awesome to get so much sleep. And she woke up super happy and just did a marathon nursing session for 50 minutes.