The chances of conceiving in any given month are 25%, even if you do everything right, and have sex at the exact right time, there is still only a 25% chance of conceiving.
Couples are considered in the normal fertile range even if it takes up to a year to conceive.
I too was very excited my first month of trying, I figured it just had to happen, we'd done everything right, and then I wasnt' pregnant. Then the second month I miscarried, now 2 months after that we're just going to relax and wait and see what happens, if nothing in 6 months i'll go talk to my doctor.
I wish you the best, and hope you can relax and enjoy the process of getting pregnant