My husband and I started trying to conceive last month. The second week in December I tested positive for ovulation. We had sex  a few times during the window so when I missed my period last week I was really excited, but the pregnancy tests are all negative. Im over a week late now and no signs of a period. On a whim, I took an ovulation test and it's positive. Is this even possible?? I'm normally so regular. What could be going on?