I don't mean to be a downer to the party, but liz, since your temps are down below the coverline on your chart, plus AF and the test was read 2 days after you took it I would say it's an evap. As far as the OPK goes, I get nearly positive ones like this (it's still negative by the standard of the test) all the way from ovulation till about a week after AF starts. The only time they turn light for me is the week leading up to ovulation. So long as it's not as dark or darker than the control it's still considered negative. Plus, an HPT will turn positive before an OPK will in relation to pregnancy, so I wouldn't put any meaning into the OPK at all.
You can take another test and read it at 5 minutes tomorrow, but with your temps being in the pre-ovulation range, it would be very unlikely that your temps would do that while you were pregnant.