Pink discharge

I'm 7 days late for my period and am having the tiniest pinkish discharge when I wipe on and off today.
 I honestly would have missed it if I wasn't so neurotic about checking right now!
I'm guessing it's AF coming because it's way too late for implantation bleeding :/ 
BFNS too. My tits are huge though and I've had heart burn non stop. Idk guess I'm talking to myself lol.