Theres no stamp on my passport about when I actually left the states though...Would that affect anything? I just have stamps on when I entered Amsterdam and etc. I mean, how would they actually know I was only gone for 3 months vs. 6 months?

I literally checked in at the airport and left. The airline looked at my passport but no one scanned it.

Sorry for the ignorance btw. Border control tends to shake me up.