first, i wouldnt worry unless you have used ovulation tests for a few months.
just go to early pregnancy tests .com and order a bunch of the ovulation sticks, they are so much cheaper than the ones in stores. you start using them on day 12 after you period and MUST use daily at the same time. it will tell you exactly when you are going to ovulate. the first time you get a dark blue line, that means try that first day and the next, and you should at least know you are on the right day. they are also so much cheaper than over the counter brands(but if you dont mind the expense, just go to the store today and buy a test set to start tomorrow)
even if you are trying the exact day, there can always be something wrong with the egg which then will not result in a pregnancy. but with the sticks, you at least know the right time and in turn, the right time to take your pregnancy test. if using theses tests, you still dont get pregnant in 6 months, go to your doctor. they will take you seriously when you tell them you were using the tests versus not.
i have very irregular periods, and these tests helped me get pregnant with two of my children the very first month. i didnt ovulate until at least day 22. thats way over the 14 day average. i would have always been trying the wrong time if it werent for the tests.