Baby sleep question... please help!

Baby boy is 5, almost 6 weeks old. He started sleeping 5-6 hours at night around 4 weeks. The last few nights he’s been waking up after 3 hours. My initial thought when this happened was to get him out of bed and immediately breastfeed him...but lately I’ve been standing over his crib and lightly shushing and singing and he falls back asleep. Is this okay? Or does he cry because he needs to eat? Should I always try feeding him? He has been waking up around 3, I’ll help soothe him and he will generally sleep again until 5 or 5:30.