Slowplay is inherently a sacrifice of your read based on your assumption that you don't need a read. When you smooth called preflop you sacrificed a read with intent to trap. You went flying without a parachute. Unfortunately for you, shit happens sometimes when you don't extract your proper reads out of arrogant notions of entrapment. That's exactly what happened. In essence, you got your hand stuck in the cookie jar.

When you have a hand like AA, what you have is one kick ass pair that's next to impossible to lay down. It's even harder without a read. The only way your not losing a crapload when behind on an uncoordinated board with AA is if by patterns of betting you can deduce and sniff out another high pocket that smacked a set or broadways that hit two pair.

Usually with AA, you have to be weary of 4th and 5th street action. One pair can't take a lot of late action.