21 days late BFN

Haven't been on birth control for 7 years. No stress. Very boring regular 4 day periods that come every 27 days... LMP was Feb 20th. Was suppose to start March 16th... And my April period was due 2/3 days ago. I got nothing... But sore breasts, occasional nausea, and DH says my breasts are fuller and I'm "tighter". What yall think? I have a doctor's appointment May 4th. Just curious...