What's going on??

So my period was due Thursday and still has not started. I have been off birth control since February and haven't missed or had a late period at all. We are recently married and not exactly trying to get pregnant but wouldn't be upset if we did. So we got back from our honeymoon a week ago today. I tested when we got back home and it was negative. Waited until today to test again since my period has not started and another negative.