BB's natural suckling can always get more milk than pumping. So don't worry.
Anyways, your BB is so small. You should really only direct BF.
BB feeding for 15 minutes - if he was feeding quickly and efficiently, it should be enough according to BF handbooks. But if he was feeding very slowly, I would try to wake him up in 1-2 hours' time.
I have a similar problem when my baby is 1 week old. As he got "yellwo", he was very very sleepy. But try hard, you can overcome it. There are several effective ways to wake up the baby:
- takes his clothes off so he will know that he need to eat;
- "out" his foot until he wake up
- "out" his back
- message his ear bud