Should I be worried?

Babe is 6 months old. Went from nursing on both sides at a feeding to only one now. Diapers are staying the same as far as good output. He seems happy but I’m worried my supply will dry up if he doesn’t eat as often/much as he was just last week. His feeds are also shorter, 15 minutes being the most (when he uses both sides), barely 5 if one side. At night he nurses a lot longer though. I just can’t explain why he went from both sides to one. We also have not started solids yet, waiting to do blw.