How confusing for you!
Have you tried giving hte ABA a call - 1800-686-2-686 - they may have lots of great advice ad support for you. Do you have support from a lactation consultant?
Long feeds are pretty common at this age. Are you switching sides during this time or is it all on one side? Swapping back and forth during a long feed is one way to get more milk into them, rather than waiting till they're 'finished' first.
How many wet and dirty nappies? That's the best way to tell how much milk is going in.
Sometimes they fuss at the breast and want to feed all the time for comfort and security as much as for nutrition. It may also be related to the sleep thing (if getting overtired).

The 45 minutes of sleep is a real pain, but, also normal. a baby's sleep cycle is 40-45 minutes. Ideally they'll sleep through 2-3 at a time, but sometimes babies will wake as soon as they get to the lighter phase of sleep again and that's it! You can try resettling, even going in at 40 minutes and standing ready to resettle as soon as they stir. OR else try different ways of sleeping - like using a sling or carrier.