preemie baby

Emilee
My son was 5 weeks early and since we've been home has been EBF. (Supplemented to be able to go home sooner)
He's 10 days old now, but when I woke up this morning my breasts were not sore.... and he only ate off one side for 16 minutes, he usually does 10-15 minutes on each side. 
Could my milk already be regulated? 
Not complaining, I used to ice my breast once a day(mainly before bed) because they were always so sore. 
I know he'd cry if he was hungry so am I just over thinking this mornings one side feeding?