opp is REG 24/19/2.3

I guess i'm just a POW here and this should be a clear fold? how do you generally interpret these sorts of plays, basically they surprise and confuse me and I end up calling too often here.

$1/$2 No Limit Holdem
5 players
Converted at weaktight.com

Stacks:
UTG Charlotte83 ($234.60)
CO PREDATOR1986 ($386.65)
BTN Hero ($407.00)
SB -maldoror- ($197.80)
BB Big-gum ($234.85)

Pre-flop: ($3, 5 players) Hero is BTN
2 folds, Hero raises to $6, -maldoror- calls $5, 1 fold

Flop: ($14, 2 players)
-maldoror- checks, Hero bets $10, -maldoror- calls $10

Turn: ($34, 2 players)
-maldoror- checks, Hero bets $25, -maldoror- calls $25

River: ($84, 2 players)
-maldoror- bets $52, Hero calls $52

Final Pot: $188