Feedings and introduction

My son was supposed to be born 1/24 . I was admitted into hospital at 30 weeks and was going to stay there until 34 weeks . My son decided to come on 11/30/2019 at 32 weeks . He was in the nicu since two days before Christmas . He was 3lbs and 8oz and earlier this month he was 5lbs and 1oz .

Question : he was eating every 3 hours on the dot now he is sleeping longer . He is drinking 4 ozs but sleeping at 5 hours sometimes 6 . Is that normal . I have to wake him up at three hours but he doesn't seem very hungry until about 4 hours .