What is going on?

Alexis

So my <a href="https://play.google.com/store/apps/details?id=com.glow.android">glow app</a> says period is 1 day late but I ovulated late this month for some reason. I got my peak on the 16th so I am technically around 5-6 DPO. We baby danced twice the day of my peak but I have been feeling some cramping since yesterday & today I noticed I have some chunks of uterine lining- no blood, just small pieces of uterine lining discharge. Could this be implantation? Or what could cause this. I don’t anticipate my period starting until the 29th of November to December 3rd because I ovulated late this month. I use OPK’s and BBT to track ovulation.