My cycle days are longer than 35 making the calendar prediction of ovulation unreliable i need some help please .

I’m testing for PCos since I’ve failed to conceive for a couple of months despite tracking ov by strips… as I can’t do it any other way and it running in the family.

I want to conceive is there any method for tracking these kind of irregular periods and I can’t always rely on the strips I’m really struggling and I’d hope someone who can relate could help shed some light