Implantation??

So af due in 5 days. I've had a headache for the past 6 days ( very unlike me, I never get headaches) this morning I got very light pink discharge when wiping but that was it no more through out the day!! Had bfn yesterday and today ( is this normal as the pink has only just happened will it take a few days if it's a bfp??) My boobs feel heavy and sore. Could this be implantation bleed?? What were your experiences?? Please help me my minds going nuts!!