growth spurt?

grayson went to sleep at midnight last night almost right after he finished a feeding. he didn't wake up until 10 a.m. this morning. he ate quite a bit then, seemed normal and happy and stayed awake until about 11:30. he went back to sleep very easily and has been sleeping since. it's 2 p.m. i've been checking on him a lot, and he's just sleeping away. i know babies do this on occasion (you know, sleep through the night and take naps...), but it still sorta freaks me out!