Strong cramps, no period

I am on day 3 on cramps that range from non-existent, to dull, to very painful and sharp. My period is not due for another 2 days (meaning the cramps started 5 days before period was due). I have had no spotting or discharge of any kind. Has this happened to anyone else? I typically get dull cramps the day before my period, but this started very early and has been very intense.