FFS, why do I keep flopping these boards with AA OOP?

I think I have to bet this turn hard in order to protect my hand. The problem is he can be shoving here with soooo many hands I think I have to go broke here, no?

$0.25/$0.5 No Limit Holdem
4 players
Converted at

Stacks:
CO ($43.40)
BTN ($10.45)
Hero ($51.20)
BB ($77.80)

Pre-flop: ($0.75, 4 players) Hero is SB [Ad]
CO calls $0.5, 1 fold, Hero raises to $2.5, BB calls $2, CO folds

Flop: [Jd][9d] ($5.5, 2 players)
Hero bets $5.5, BB calls $5.5

Turn: ($16.5, 2 players)
Hero bets $16.5, BB raises to $40

Yeah go broke.

your gonna fold for 20 after investing 20? This is a terrible spot, but once you make that turn bet you basically have to call...you beat some of his range too so its not horrible.