Night feeds super short compared to day feeds?

My 5 week old feeds SO fast at night - 1 boob for only 5-7 mins and then done / passed out immediately (barely awake during feed). Try to offer other side and not interested. Daytime he is going much longer, about 45m feeds average and both sides. He is generally a fast feeder and I do have a quick let down, and good supply. Anyone else experiencing this?! Anyone know why this is? I’m not

Complaining, just interesting how different day and night feeds are!