6 week old suddenly sleeping a lot

C
So my baby boy was eating a ton /fussy and not sleeping much for about a week, now the past three days he's sleeping a lot more throughout the day and in about 5 hour stretches at night...& is back to eating his normal 4oz every 3 hours. No signs of him not feeling good at all. Should I worry? Or chalk it up to a growth spurt? First time mom if you can't tell 😬