What could this be?

Nattie • N V Cull
So guys I'm 6 days late. 
Period was 16th Jan, and ovulation was last week of Jan. 
Had sex 2 days ago, and had 5 spots of pinkish blood and nothing since. 
Nurse said she could the faintest off line forming, still got negatives til then. She told me to come back next Wednesday, praying I'm pregnant. Advice? What was the blood?