cramps but no period?

[juice-by-alex.livejournal.com]

Usually a day or two before I get my period, I get really light cramps and a sort of weak feeling in my stomach and knees. Also, my period is usually freakishly regular.

I've had these cramps and that feeling for over a week now (my period was due about 10 days ago), and yet my period won't come. I'm not sexually active, this is the first time it's ever been irregular, and it's the first time I've gotten my premenstrual symptoms so long before seeing my period. I'm not really worried much, but I just wanted to check if this was normal. Insight please?

Thanks. :]