No fat in breastmilk?

My ds is 3 months old and eats like a champ, lol. I don't usually pump because I'm a sahm so I can feed him directly.last night I went out for about 6 hours.my ds eats about every 2 hours sometimes more frequently, like just before bed and upon wakening and sleeps 8-10 hours at night,gaining weight etc.my question is...I pimped last night when I got home and this morning I saw milk in fridge.there is virtually no fat on top since seperating and I remember from previous pumping with him and my dd that there was a lot if it.I'm not dieting nor am I eating no fat, just ask my butt my belly and my thighs lol.ww do occasionally supplement with formula and he'll take about 9 ounces like its nothing and be satisfied for 4 hours. Am I not producing quality milk and so je had to murse more often I guess is finally my question.thanks all!