My period is about a month late, what could cause this? should i be worried?

It depends: If you are sexually active, even if you have not had unprotected intercourse, you should check a pregnancy test. If you are not sexually active or your pregnancy test is negative, it is likely that you did not ovulate at your normal time. This can happen to anyone from time to time. If your period is more than 2 months late, you should see your health care provider to help find out why.