you've got a one-card straight, the second nuts, you've put in 22 blinds, and it's 132 more blinds to get to showdown. you could fold if you want because you don't have alot invested, but i like calling, think he does this with two pair+. calling should be very +ev even though he does have 75 sometimes. (you need 42%, i'd think you're more like 55%)

you can stab half pot on the flop here with a gutshot and over and bdfd, you'll take it down alot. raise turn bigger, you have a big hand, build the pot.