I am having trouble knowing what to do in this situation

[FishAndChips]

Having not bet the flop, I would consider raising the SB's bet on the turn-- if you think he'd bet out with any pair. You'll scare the pants off of anyone not holding at least a K with a good kicker. The turn was a rag. There is no flush draw and the straight is not too likely. Your preflop raise could make your check on the flop look like an attempted slowplay, representing something like AK, AA, KK. I'd have to gauge the players, but it's something to think about.