I hate the fold but...

I had to be beat here.... no reads, 3rd hand at the table. Calling just seemed like a waste of 15 BBs, esp when the only hand I beat was an underpair.

PokerStars No-Limit Hold'em, $0.10 BB (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

UTG ($9.15)
UTG+1 ($14.60)
MP1 ($4.90)
MP2 ($6.75)
MP3 ($15.30)
CO ($10.45)
Button ($3.80)
Hero ($9.80)
BB ($9.40)

Preflop: Hero is SB with J, J.
UTG raises to $0.4, 2 folds, MP2 calls $0.40, 2 folds, Button calls $0.40, Hero raises to $2.25, 1 fold, UTG folds, MP2 folds, Button calls $1.85.

Flop: ($5.40) A, K, 6 (2 players)
Hero checks, Button checks.

Turn: ($5.40) 6 (2 players)
Hero checks, Button bets $1.55 (All-In), Hero folds.

Final Pot: $6.95

You're probably beat, but the pot is $5 and he only has $1.55 left, so I think you have to shove the flop. It's possible he has a lower pair than you or something stupid like QJ. The pot is too big to fold here IMO.