Growth spurt

I have read that growth spurts tend to occur in the 3 week, 6 week, and 3 month. I know that there is no normal or usual when it comes to babies, but Liam is 2 weeks old and will not stop eating. Could he be going through a growth spurt already? He was a week late, and I dont know if that matters. Last night he took 10 oz in 5 hours. He usually take 3 oz every 3-4 hours and sleep very soundly in between feedings. He was much more fussy than usual too. I know he's been very gassy, and I think that is my fault for eating some things I shouldnt have. Are there other signs of a growth spurt than eating more?