Pink spotting? Pls help!

Af is due tomorrow, and normally comes on full blown like I'll wipe and the red blood will be there and within minutes it gets progressively heavier and then come the cramps. Well I wiped and saw this pink spotting, only on tp, not on underwear or pad, thought it was odd but must be my period. 30 mins later still no blood and I wipe it's clean. Could it be possible ib bleeding? I've never had pink spotting for as long as I can remember, and I'm not having any cramping, just a minor back ache. Could it be implantation bleeding, at 12dpo one day before af? Anyone have any similar experiences?