3 weeks late, BFN, abdominal pressure

Hello! AF is 3 weeks late today, and is normally pretty regular. I feel normal for the most part, but have this slight pressure in my abdominal area on the right side. It's not painful, just a bit uncomfortable sometimes more than others and it's been like this for probably 6 weeks or so. All of my tests have been BFNs. I plan on making a Dr.'s appt. this week, I'm just wondering if any of you ladies have experienced this too?