How to know my DPO based on OPK?

Hi 😊 I’m trying for a baby this month, my last period was the 29th of December and my last cycle was 32 days (I didn’t measure before that).

Anyway going by all my apps I was due to ovulate on the 15th of January, but I actually had a very dark positive OPK on the morning of the 11th of January - darker than the control line! The next morning it was lighter but probably as dark as the control line. The next day after that there was barely a line.

Do you think I ovulate don’t the 11th or the 12th? I’m either 11dpo or 12dpo. I’m also a bit confused because I read that luteal phases are around 12-14 days, and my due date for my next period is in 6 days - meaning I’d be 17/18dpo! I’m guessing my cycle length must be different this month?

Not sure when to test either, I might be symptom spotting but I feel very fatigued, I’ve had some mild cramps a few nights ago, and my CM has increased!