Yeah, I'd definitely take another pregnant test and keep testing. If you get negatives again, make an appointment for a blood pregnancy test. Your chart does look like a pregnancy chart (not much of a shift change but it IS a shift change). The only other thing that would keep your temps up after O would be an ovarian cyst. I really think you're preggo but you'll have to do another test. OPK's can pick up the pregnancy hormone just like an HPT so that's a good thing.
Good luck! And let us know!
I'm not sure why you had another +OPK on cd 39, but by looking at your temperature curve, it really seems like you did O a while ago. Have you thought about taking a home pregnancy test? I would never have been able to hold out this long! :) Good luck to you.