I usually play SNG, STT & MTT and am advanced there with a good win ratio. Last night I played .5/1NL shorthand on Noble to collect some crowns for their 50% reload bonus.

I got AQo and SB, two callers before me so I decide just to call. BB calls and the flop comes down as
2 4 Q rainbow
I bet $3, BB calls, other two fold
Turn is 5
No flush possible I bet the pot $10
BB calls
River is 3

What should I have done here?

What happened is that I bet $20 - he raises to $40
I was pretty pot commited so I called
BB fold over 67o!!

Bad beat or bad play? Feedback is appreciated.