19 days and counting...

none
I got my copper IUD in February of this year. Since getting it, my periods have been like clock work. Some long and light, some short and heavy, but always start on cycle day 30. I did not have a period in November. I'm 19 days late and no sign of Aunt Flo. I have tender breasts, nausea, fatigue, slight cramping, and a negative home pregnancy test. Has this ever happened to anyone else? Don't get me wrong... I hate my period as much as the next girl, but I'm slightly worried.