My baby is 6 weeks old in the last 24 hrs she was spitting up the milk she was being nursed and she just slept 7 hours without waking for a feeding?

It happens: Even healthy infants spit up occasionally & may begin to reflux & empty their stomach as they get older. Reflux actually peaks at 3-4 mo when they have more muscle tone & haven't started to sit. An infant can sleep through the night without a feed as early as a week. If they are active & maintaining their usual activities it is likely normal for them.