so maybe i will just let it happen when it does, instead of stressing myself out each and every day
I'm sorry it didn't work out for you this time. Do you normally have long cycles? If so, I understand it may be difficult for you to know when ovulation is approaching.
I found a site that gives estimated days to start testing up until an average length of 40 days. It says with a 40 day cycle to start on day 23. However, I don't know if this will be to your benefit.
My best advice would be to temp. Do you temp or track cm? Temping will confirm when you ovulate and therefore also helps you to determine your luteal phase length (time between ovulation and next cycle). You get a special BBT thermometer, which is available at many places. I got mine at Wal-Mart for $8-$9. You take your temperature every morning before getting out of bed, moving a lot, talking, drinking, etc. It gives you the base temperature. You add this to your chart. The pre-ovulation temps are lower, then after you get three higher temps your ovulation will be confirmed. Then you are in the luteal phase/tww where your temps will be higher. This will definitely help you find a pattern over time (in case you need it).
You are supposed to ovulate 24-36 hours after a positive opk. This may vary based on the brand you use. However, the thing that is horrid about them is that they can be positive, your body struggles to ovulate, but then you assume you ovulated when it actually didn't happen yet. That's why some get multiple positives throughout the cycle.
My advice until you have a general idea of when ovulation happens is to get a tally of your cycles. Take the shortest and the longest. Then look at the calendar, count off to the shortest possible next af date and the longest possible next af date. For example: maybe between 55(shortest)-68(longest). Then count back 12-14 days from the shortest and then 12-14 days from the longest. Perhaps a week before that range might be a good time to start testing or to assume you might be near ovulation. We are normally supposed to have 12-14 days between ovulation and the start of the next cycle. This varies as well.
Another idea: bd at least 2-3 times each week hoping to catch ovulation until you have a general idea of when it happens. I'm sorry it is so difficult. I wish it could all be easier. Good luck!