S.J.
All three of my nursing babies did the same thing.
The only thing I can tell you is that it is normal, at least in my experience.
Also, he may be having a growing spurt and needs those extra night feedings - he is just picking an inopportune time!
Make sure he eats plenty during the day. I always noticed with my babies if they ate less during day, even if just a little less at the breast on one feeding, they ate more in the middle of the night. Try keeping him very satisfied all day. Instead of only nursing every three to four hours during the day, offer the breast every two and see if that helps. It helped with all three of mine.
He wants mommy's love at night! I know it is tiring, but love on him and try to sleep sitting up!! My youngest is 8 months now, and this stage you are in will be gone before you know it!
Best wishes......