I've been having bad cramps recently and have skipped my period this past month. i'm 100% pos i'm not pregnant. is there reasoning for this?

Anovulation: If you missed your period and your pregnancy test is negative on one occasion, it never hurts to repeat it in 2 weeks just to be on a safe side. If negative, the next most plausible cause of your missed period is anovulation - the absence of ovulation. There is a good chance it will come next month, but it may also result in an unexpectedly heavy irregular bleeding any time.