I like to think about what hands would i c/r with in this situation if i was the sb.
set
34
2 pair
or an overpair

its easy to see the sb completing with all these hands, so you have to figure out why is he c/r. all of these hands would want to win the hand on the flop because of how drawy the board is. so your gutshot may be to a split and your only hope imo is the flush. if my math is correct there is now $15.50 in the pot and you need to call another $5 which is 3-1. with your hand i fold.

But i suck