DD is seven weeks old and I'm at a loss to know what to do about her sleep. She sleeps a lot during the day then at night she'll be awake for hours, not going to sleep until 2 or 3am. Several people have suggested keeping her awake during the day so she'll go to sleep earlier at night and DH and I tried to do this yesterday, although there were some times when she was just too sleepy to be woken. But then last night she wouldn't settle for hours and seemed really upset rather than just awake 
Got her up at 9 today and tried to keep her awake but she was just falling asleep again and then became really upset. At this point DH and I decided to let her sleep because she was distressed but she then found it really hard to settle
We're wondering whether this is what happened last night - that she was overtired, but we don't really have a clue and we're so tired ourselves that we're probably not thinking all that straight.
DD is just waking now from a nap of nearly two hours, so have we now created a problem for tonight? How can help her to sleep during the night without making her miserable?