Period is 16 days late

So long story sort of, bear with me. My last period was September 13th and I had some spotting from the 29-2nd ish? Which was when I was supposed to ovulate according to this app. It was all brown and pink. Little tiny bit of red. Was never enough to wear a pad. Fast forward to this month and still no period. I had a blood test done October 21st and it was negative. She told me to come back 4 weeks from the spotting Incase my body had a weird early period. So I’m scheduled for repeat blood test Wednesday. Anyone ever gone through this??