What is going on??

I have a question. Anyone ever had a period that's 39 days late? I took 2 pregnancy tests last month and they came back negative...still no period, no symptoms, but still can't figure out why my period is this late. My fiancé is a little concerned because I haven't had a period since June 28, and believes I may have a bun in the oven. Any one have any advice or suggestions? Thanks 😊