Is this a growth spurt thing?

My 7 week old all of a sudden keeps sleeping! He's usually really awake and alert but since yesterday he slept all day... I couldn't even wake him for his last bottle I feed him it while he was still sleeping and then eventually I got him to wake up! He stayed awake for less than an hour and then fell asleep all night! He normally wakes up 4/5am but I woke him this morning... is this what happens with a growth spurt? He's never normally this sleepy he normally stays awake maybe an hour and half after each feed but he literally slept all day yesterday? :/