BF question

First time for breastfeeding.. so I'm not totally sure, of anything lol
But sometimes after a long stretch of nursing/pacifying on my breast, little guy will come off the boob, once placed back on he starts fighting it, like he's not pleased with it, or something. Could this mean he has emptied that breast?
I will add that he will be one month tomorrow, he has a great latch (as checked by multiple professionals) and while I don't think my milk supply is great, I do know he gets quite a bit.