Faint lines

I have take 3 ultra sensitive tests and gotten faint positives. AF is due in 5 days and today I started spotting really light pink with very mild cramps. I can't even really call them cramps but just a slight pain. The pink cm is only when I checked my cm and it's not when I wipe. Is it late in my cycle to have implantation bleeding and wouldn't I gotten bfn yesterday and this am if it hadn't occurred yet?