19 days late...

So I’m 19 days late ! And idk what going on I’ve taken pregnancy test and they show negative. Has anyone else had this happen ? I’m usually very regular . I did have a miscarriage in December but had a period on Jan like clockwork sooo I have no clue what it can be now? Am I just skipping a period? Any opinions or anyone whose gone thru something similar? My appt is April 6