I think with the checks on the turn, I could discount the boat. I think the river action increases the chances someone made a BDF but I don't think a call is out of line.
I know how you feel. This happened yesterday.

Hero has AJo in CO.
EP limps,folds, Hero raises,fold, SB calls, BB calls, limper calls.
Flop T[img]/images/graemlins/diamond.gif[/img], J[img]/images/graemlins/spade.gif[/img], Q[img]/images/graemlins/club.gif[/img]
Checked to Hero who bets, limper folds, blinds call.
Turn 3[img]/images/graemlins/diamond.gif[/img].
Checked to Hero who bets, blinds call.
River A[img]/images/graemlins/diamond.gif[/img].
SB bets, BB raises, Hero thinks....folds.

BB takes down hand with AJ.