Help!!! Af only showed for 4 days??

Kr

Hi ladies I need some thoughts here... I had a mc on 3/22 and bled for 8 days, started right away ttc but af showed up on 4/22 a day early according to my charting. I’ve been bleeding pretty heavy up until yesterday evening where it was mostly spotting and still only spotting this morning. I usually have a 30-33 day cycle and I have always pretty much bled for 7 days and I’m so regular like clockwork! This is the shortest cycle I’ve ever had. We’ve been ttc for 8 months for #5 and I am 41. We’ve had 3 mc’s Nov, Feb, March. I had tests done after this last mc and everything came out fine and we have been encouraged to keep ttc. Should I be concerned? If this is the end of af when should I start using opk? Still on cd 10?? TIA!!