Does anyone know if my luteal phase length can change cycle to cycle?

Hi everyone,

My cycle is always smack bang on 28 days, and it the past I've always Od right when I'm meant to, around day 14 or 15, but this month I'm sure I O'd around day 10, felt O pain, and had heaps of EWCM. So of course we bd then , hoping to catch the eggie, and i spent the next 2 weeks waiting and waiting. I though one's luteal phase was always around 2 weeks, so i was expecting AF to come a bit earlier, but here I am, 2 and a half weeks past what i thought was O day, and still no AF??!

I have tested heaps of times this month already and BFN...does anyone know whether O date can change in each cycle, but cycle length stay the same?

Or did i O at normal time and missed it?

Oh its all too much!!

Thanks in advance!