breastfeeding

so I have been pumping In the mornings and getting anywhere from 2 to 3 oz, but this evening I felt my boob was hurting a little and pumped while my son was on the other one. I only got 1oz and after he fell asleep and was done I tried to see if I could pump any from that boob he was on and nothing. so my question and concern is am I running out of milk later in the day or is my milk supply not keeping up with my son?? because the last 3 evenings he wants to be attached non stop even if he just has the nipple sitting in his mouth. and didn't want anything to do with a paci yesterday. he has the yellow runny stool and anywhere between 6-8 dirty fiapers a day. and i am told those are good indicators that he is getting enough milk. TIA for any opinions