Contradictions in test results.

We have been ttc since October and this month my period is eight days late. I didn't have a pregnancy test and I'd read that you can take a ovulation test as well and since I shouldn't be ovulating I thought why not.  So the ovulation test is positive. ( I have tried 2 since the start of my missed period) but today when I took a pregnancy test it says not pregnant. What gives?!?  At this point I'm over a week late. Should I still bother with going to my obgyn? Is the ovulation test an actual good test or just a possiblity? What should I do?