Oy. Six weeks was hell for us here.
I was still trying to work out cues too.
Part of our problem turned out to be reflux, so I had to keep both babies upright for 20 minutes or so after a feed, which helped - yay bouncy seat.
All you can really do is follow cues as best you can. If you haven't dealt with the 6-week growth spurt yet, odds are you will soon, and everything will be topsy-turvy yet again. Meanwhile, if he wants to sleep, by all means let him unless he's significantly past his feed time. The time will come soon enough when you can feed him, take him to the grocery store, come home, play with him, and THEN put him down for a nap - hard as it may be to believe now.