10 days late but not pregnant!??!

Hey guys just after some advice please. Im not on the pill or anything, been like this for over year now... last time my period was this late was around the time of my wedding. Anyone know why it could be this late other then stress? I don't feel stressed other than worrying about this lol I might go to the doctors next week if it doesn't come? I took a pregnancy test the other day and it was negative too