My period is usually like clockwork, i get it the same time every month its very regular. I have not been sexually active for the past year so pregnancy is not possible.

Last month my period came 2 days late and everything about it was normal except that i was still feeling menstrual cramps for about a week after finishing my period. This month my period is now 10 days late but i still got the usual back pain and slight menstrual cramps that i usually get during my period but still no blood. Now the back pain has diminished but my lower stomache still feels tight and i'm still getting the occasional cramp or discomfort through out the day.

Are these symptoms anything i should be worried about?

Also; I was in a car crash (no injuries) a few weeks ago, which maybe have something to do with it? (stress?)