2 weeks late,

Ok so I'm always on time never late. ( I have a very regular cycle) I was 2 weeks late just started a light flow last night took a pregnancy test came out negitive. I was even nauseous some morning and a couple of evenings, I really thought I was pregnant just b/c I know my cycle. Has anyone ever been this late and had there period and ended up pregnant?? 
Thank any suggestions please help!!