You've had some great suggestions already. I'll see what I can add about the breastfeeding issues, though.
Aubrey had a good question about how long it's been going on. If it's only been a few days, it could definitely be a growth spurt. If he's always been so starving, it could have to do with supply. Actually, a lot of moms may not feel that full, so that's not always a good way to judge your supply. Same goes with pumping - some moms can't pump much but have normal supply.
First, a few questions... How is his weight gain? Does he have lots of wet and dirty diapers? Are you single or double sided feeding? Do you do breast compression to make sure you're really emptying a side before switching? If supply is a concern, there are lots of ways to help that.
Another option is to do EAEASY. In other words, you feed, have some activity, then feed again before the nap (although not to sleep - so really brief A before sleep). This will make sure that hungry won't wake him. Then you can be confident using pat/shh, swaddling etc, to extend the naps. If he's having 45 min naps all day, as the day goes on, he'll be getting fussier and fussier, and may just be asking to nurse to calm and soothe himself.
Let me know if that helps at all, and if you have more questions!