I have a almost 7 week baby whom I always nurse her to sleep during midnight feed. She would suckle for 5-10 min before she drifts back to sleep again. Sometimes suckling time less than 5 min. She wakes up every 2 hours. I wonder if she eats enough this way? Should I wake her up or let her sleep?

What you are doing is feeding on demand, which is correct. Babies around this age drinks every 2 hours. As they get bigger and their tummies can hold more milk they usually eat every 3 to 4 hours. Hence you do not need to wake her up. You can look for these signs as an indication if your baby hungry: *moving their heads from side to side opening their mouths *sticking out their tongues *placing their hands, fingers, and fists to their mouths *puckering their lips as if to suck nuzzling again their mothers' breasts showing the rooting reflex (when a baby moves its mouth in the direction of something that's stroking or touching its cheek) *crying