Af arrived! :(

Used preseed for the for the first time this month, but still Af arrived today.. I'm so heartbroken, as I really hoped that this was our month finally, as I used preseed.. After hearing all the success stories of many others using it and getting pregnant at the very first time, made me think that I conceived for sure... But now I feel everything has gone blank, I am crying... Is there still hope for me the next month? Can I concieve the next cycle by using preseed again..?? Can anyone tell if not once, how many cycles does it take to concieve using preseed?? Plz share ur success stories, tell if u have concieved using it the second, third or fourth time... I am already taking clomid for  ovulating, and I have only two more chances to take clomid... :(:(