Help Please!

My period is 4/5 days late with negative test after negative test. My period being late has only happened one other time in my whole life and it was when we were trying to conceive our first child in 2015. It was a whole week late that time. So, 2 questions:

Has anyone gotten their first BFP a week after your missed period?

If I don’t have a period to go off of how do I calculate ovulation? I’ve never tested for ovulation before but is that the best way to go now?

Thanks for your help.