50NL set vs possible straight

[pokahpaul]

PokerStars No-Limit Hold'em, $0.50 BB (5 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Button ($49.75)
SB ($38.65)
BB ($106.95)
Hero ($50.60)
MP ($48.70)

Preflop: Hero is UTG with 8[img]/images/graemlins/spade.gif[/img], 8[img]/images/graemlins/heart.gif[/img].
<font color="#CC3333">Hero raises to $2</font>, <font color="#666666">1 fold</font>, Button calls $2, <font color="#666666">2 folds</font>.

Flop: ($4.75) 5[img]/images/graemlins/heart.gif[/img], 6[img]/images/graemlins/diamond.gif[/img], 8[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $4.5</font>, Button calls $4.50.

Turn: ($13.75) 4[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $5</font>, <font color="#CC3333">Button raises to $15</font>, Hero calls $10.

River: ($43.75) T[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">Button bets $28.25 (All-In)</font>, Hero folds.

Final Pot: $72

no reads on villain,
please comment on all streets