Implantation bleeding or period?

Hello, I’m coming into cycle 3 of ttc our first child. Have had 2 Af’s since coming off the pill in late November. AF is now 4 days late, I ovulated 24th jan based on CM. Yesterday <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">eve</a> and this morning i have had vv pale brownish pink CM, still no sign of AF. BFN on testing. I am so regular normally (pre and during the pill) I’m thinking my hormones are just a bit all over the place? Any ideas/advice would be greatly appreciated as all so new to me... I’ve only just got used to the abbreviations haha x