Late period=problem?

[sleeping-hare.livejournal.com]

Hello, everyone. My period is about a week late and I'm starting to worry. I've always been irregular, but my cycles are usually between 21 and 28 days, my period coming either early or right "on time;" I have not been extremely early or extremely late since early high school. I know I could not be pregnant since the last time I had sex (which was protected) was a over a year ago, but it is just an irrational fear of mine. I have not really been under a lot of stress this month, either, but if I were then my period comes early due to stress. Have any of you ever experienced this? Should I go see a doctor or perhaps wait another week to see if my period starts up?