Breastfeeding to Bond?

I breastfed my son for the first week or two of his life before I began pumping and giving him breast milk in a bottle. Since then, he hasn't searched for my nipple to feed and rarely ever wants to feed off me at all. However, the last couple days, he's been moving down to my breast when placed on his belly on my shoulder. He licks, feels and searches until he finds my nipple and latches on and drinks until he falls asleep minutes later. I returned to work Monday and have been leaving him with my mom while there. Do you think he is only doing this to bond with me and comfort himself since I haven't been around as much?