5 days late, negative testd, still no period

I've taken three tests now, one on the day my period was due, negative, one yesterday at 4 days late, negative and one again today 5 days late, still negative but no sign of Flo in sight. It took until 3 days late to finally show positive with my first. I don't feel like I'm going to get my period but I don't necessarily feel pregnant either. I'm NEVER this late. Last time I was this late I was pregnant. Im using clear blue so I know they are good tests so I just don't know what to do or if I should call my doctor. If I'm not pregnant something may be wrong. In the 20+ years I've had my period ove always been like clockwork plus or minus a day or two at most. Any thoughts or guidance would be so appreciated. We've been TTC for over a year now for #2.