Spotting or IB?? When should I test again?

According to my Glow calendar, AF is due today. On Thursday, 6/20 I had one small streak of brownish blood when wiping. Took FRER test Friday morning 6/21 and was negative. Had a little more pinkish/brownish spotting on Friday. Just when I wiped and not every time - maybe every other time. Sometimes after peeing and wiping there would be nothing. I figured with the spotting/negative test that AF would kick in full force by Saturday. Yesterday came and went, no increase in flow and just very minimal pinkish/brown spotting about every other time. I do spot a few days before my period, but it gets heavier each day and much darker blood. This morning - still no AF and barely any spotting when wiping.

So my question is - is this most likely just AF taking foreverrr to start or is it possible for implantation bleeding to still be occurring and if so, how many days should I wait before testing again?