How do you know for sure that your ovulating I was taking the Clearblue digital ovulation test kit and got my surge on cd15 and I got it again on cd25. Just because you get a positive ovulation test doesn't mean your actually gonna ovulate does it?
It's not very ideal, but I'd say the best way to know for sure is a cm check, free at home in your own bathroom. Look up fertile cm and check daily until you have it. Two types are fertile and two are not. It's free and effective, worked for me the first month!
If its not much, or sticky and like curdled milk, it's not time.
If its creamy, like lotion, ovulation is coming soon. Since sperm survive up to seven days, you can have sex the first day you see this type, and I'd say every other day up until ovulation.
If its wet and watery ovulation is very soon.
If its like egg whites and stretches two inches between your fingers, you are there. Have sex this day.
For the heck of it, do it the day after, the egg will probably still be alive.
I followed that plan and 6 weeks later, positive test!