Minor setbacks

Brayden has been known as a good sleeper-- slept through my mom's dog barking, slept through his hip ultrasound, I mean, GOOD SLEEPER. After the doctor told us he could sleep till he wakes up (which was at day 5) Brayden slept consistently 4 hours, and a lot of times 5-6 hour stretches. Before you gasp in disbelief and tell me how blessed I am (which I am blessed, just a bit frustrated at the moment), let me tell you about the past 2 weeks.

For some strange reason he's decided to only go 3 maybe 3.5 hour stretches. This is considered "normal" for a 5 week old, however when momma is used to 5 & 6 hours, it makes for long nights and a bit of frustration. I don't really know WHY he is doing this, but didn't know if all you mommas out there knew if they kind of divert off of the path around 5-6 weeks and then jump back on the wagon? To make matters worse, I think I might have overactive letdown, and so Brayden gets frustrated when he's nursing so he won't nurse as long. I think he's still getting what he needs because his diapers are SOAKING wet, but it's still frustrating for both of us. This has causes interrupted nap times, and so it's a never ending cycle. I am following Babywise, and for the most part he follows the 2.5/3 hour schedule (more like 3 hour schedule), and before all of this change he was going down awake and sleeping through all of his naps. Any suggestions from someone who's been there done that????