Cycle weirdness

Gena • 37. First time mommy to baby James on 06/19/18.
So anyone who followed my posts the past few weeks will know that I had like a 50 day cycle and then finally AF showed up. Well, I'm someone who normally has HORRENDOUSLY heavy periods lasting about 5-7 days... This time around it was extremely light (for me) and lasted about 4-5 days. Then all of the sudden I started using my fertility monitor on CD 9 (because that's when it first starts telling you to test... And so far all the tests have come back as "high" fertility. No "peak" yet, but high. So today DH and I BD'd because two of my apps say my fertile window starts tomorrow and two of them show sometime in the next 5-7 days. But it's just so weird that I would have this extremely light period- then go straight to having high readings on my fertility monitor.