Late period, cramps and light spotting

[Firelighter9]

I usually have a 12 day luteal phase, I’m currently on 15dpo, had cramps this morning but still nothing more than some pale pink/peach spotting when wiping.
BFN on 12DPO and today, pretty certain not pregnant. But what could be causing lack of actual period?! I track temp and CM so pretty sure I ovulated on a certain day or perhaps the one after.

Hello im new here. I am due on my period tomorrow, two days ago i had two positive clear blue digital test then today i had two negatives. I had urinated twice within the hour before taking the test could this be why? Im so worried as i was so excited please tell me your experiences