Did I donk this up?

Villain in SB is 31.7/7.3/2.4 over 205 hands

PokerStars No-Limit Hold'em, $1.00 BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

SB ($292.80)
BB ($133.70)
UTG ($68.65)
Hero ($94)
CO ($94)
Button ($185.40)

Preflop: Hero is MP with 6, 7.
UTG calls $1, Hero raises to $5, CO calls $5, 1 fold, SB calls $4.50, BB calls $4, UTG folds.

Flop: ($21) 5, 2, 8 (4 players)
SB checks, BB bets $15, Hero calls $15, CO folds, SB raises to $55, BB folds, Hero ???

Yeah, that's tough. Flop is probably a fold, but meh, you made a made a mistake. When the action gets back to you, don't make another.

Unless I know UTG doesn't like to call post-flop I wouldn't isolate with this turkey.