Confused!

I had what I believe to be implantation bleeding (pic below) on 13DPO and here and there a little bit, not enough to fill half a panty liner. It stopped at 15DPO the day AF was due and looked like some clear CM yesterday. Today I’m 16DPO, testedthis morning using clearblue digital

and got a BFN. Should I wait to test again? Am I out this month? Or could I still be pregnant? Any comments or similar stories would be great x