Spotting the week before af

Not exactly sure when af is due because my cycles are irregular. Last cycle was 45 days, and I'm currently on day 43. Last week I had three days of spotting only the first wipe of the day and there was a slight pink tinge to it.. I'm assuming my period should be due this week the latest. Do you think this could be implantation bleeding? My suspected ovulation date was the 6th.