Newborn fights sleep, and wins almost always!?

My son is 2 weeks old and does fine at night between his bottle feedings, but during the day, even if he falls asleep on the bottle, he fights sleep. We give him a paci and he likes it, but sometimes freaks out as if it's fallen out even if it hasn't and wakes up and starts fighting sleep again, missing several naps in the day. I don't know how to get him to relax. I can get him to sleep by stroking his face on his eyebrows and cheeks, but as soon as I'm ready to lay him down he starts fighting again. I have a 2 year old so I can't just hold him all day. Any ideas?