How can I tell if my 4 week old is hungry or just wants to suck?

Empireceo

For the past three days it seems like my 4 week old wants to nurse hourly but he only actively sucks for 5-10 minutes, then just hangs out on the breast.  It's making me crazy!  I was told not to give him a pacifier until 8 weeks but now I'm reconsidering.  Could he just need to suck instead of actually feed? Or is it possible I'm not making enough milk and that's why he wants to feed so often?  At night he goes 4-5 hours, but during the day it seems like all I do is nurse!