$25NL - facing a river c/r

I was totally owning villain, HU (me calling down underpair and beating K high, etc), then the table filled. he doesn't respect bets at all and I think he'd call this with AT, maybe worse. He hasn't payed back on the same street that much (i.e. turn). He got his stack by some donk play vs another who sat down briefly and spewed a stack to him.

not sure what, if anything he thinks of me.

PokerStars No-Limit Hold'em, $0.25 BB (5 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

MP ($14.60)
Button ($36.15)
SB ($22.20)
Hero ($60.05)
UTG ($24.50)

Preflop: Hero is BB with A, 4.
1 fold, MP calls $0.25, 1 fold, SB completes, Hero checks.

Flop: ($0.75) T, 6, 6 (3 players)
SB bets $0.25, Hero calls $0.25, MP calls $0.25.

Turn: ($1.50) 4 (3 players)
SB checks, Hero bets $1.5, MP folds, SB raises to $3.75, Hero calls $2.25.

River: ($9) 4 (2 players)
SB checks, Hero bets $6, SB raises to $17.95, Hero

thoughts on turn?

Yeah turn is definately a fold and I fold the flop too. I guess you can call the river with your reads...