2 week old bby

does your newborn sleep at night tonight my new born is 2 week and 2 days old she usually sleep 3 hrs sometimes 2 and half the most 4 hrs she wakes her self up she gain weight everything fine, but today she been asleep for 5 hrs & 30 mins going for 6hrs i end up waking her up i got scared lol to feed her i think she need to eat, my question is if she wants to sleep longer should i let her or should i keep waking her up ever 3 to 4 hrs? does any of your bbys sleep throw the night when can start lett bby sleep as long as she wants?