Late short period, but ovulating on regular schedule

Period was due last Monday but didn’t show until Wednesday. Only lasted barely 3 days, and I’m typically a FULL 5 days. It was weird and I’m never late so I started using the ClearBlue opk 7 days after when my period was supposed to show instead of when it did just to be safe. I had one blank circle yesterday and it’s flashing this morning. Has anyone had anything like this happen? My last period was late but I’m ovulating on schedule it seems? According to Glow today would be the first day of fertility if my period had been on time.