Week late all bfn and still no period ! Help !

Period was due last sunday, had absolutely nothing no signs no symptoms of either AF or pregnancy. The only thing was a few days ago i wiped and then was faint pink blood, thought i may come on then nothing cant have been implantion because it doesnt fit the time line (even if i didnt ovulate when my test was postive i had barely had sex after). Havent stressed about it because i havent seen the point but today im fed up ! I want to start fertility testing and i cant until the 21st day of my next cycle ! Has this happened to anyone before and ended up being pregnant or ending in a period ? Help !