Too Much Sleep?

Normally, I would jump for joy if my baby slept for longer than anticipated but last night, my daughter slept from 10-5:30 without waking. She ate 3 ounces at 9:30 and cluster fed all evening. She is 5 weeks old and was more than her birth weight at 2 weeks. Is it okay to let her sleep that long without eating? Has your little one slept that long? She woke up for a few hours, ate twice and now is napping but she seems to be happy and wasn't acting lethargic. Thanks!