I feel like a glorified babysitter

Because of my job I get to see my baby 3-4 hours a week. While his grandma gets to see him for roughly 8 hours 3-5 days a week. I’m so afraid of losing my bond with my son to her. (I know. It’s selfish. And dumb) but because of this, I sometimes feel more like a glorified babysitter than a mom. And I hate it.