My cycle varies in length from month to month, ranging between 29 and 34 days. I started having cramps and pain in my lower back (which always accompanies my period) on the 28th day of my cycle. Today is day 34 - the cramps and back pain have been constant all this time, but my period seems no closer to actually starting. I ovulated approximately on day 14-15 of this cycle. I've had opaque white discharge the past few days and I've detected a slight smell of iron... but there's no blood. I took a pregnancy test first thing in the morning on day 32 and it was a clear negative (I believe that since I expected my period as early as three days before I tested, my results would be accurate...). I'm not sure what's going on!
I've been very stressed the past two weeks because of a potential move across the country that could happen on short notice, but I had just finished ovulating at that point, so it didn't delay ovulation. That said, I am rarely even mildly stressed at all, so extreme stress may have effects.
As much as most sources say that the luteal phase is more or less fixed, I am certain mine fluctuates. I always experience ovulation signs that peak EXACTLY two weeks after the first day of my period, yet the length of time from one period to the next varies considerably, though the menstruation to ovulation appears very consistent.