It might be a good idea for you to get your thyroid checked. Your doctor can draw blood and test your TSH (Thyroid Stimulating Hormone) level to make sure your thyroid hormones are in the proper range. If they're too high or too low, they can cause problems with your menstrual cycle and conception. I couldn't conceive for 10 months before I had mine checked and started on Synthroid (for low thyroid hormone levels). The next month, I was pregnant. It's not an uncommon problem and for some women it can be an easy fix, so it may be worth a test.

If you do get tested, make sure to ask for a numerical result rather than just "normal". The normal range has recently been changed to .3 to 3, but many labs and doctors are still using the old range of .5 to 5. I definitely don't feel "normal" at levels of 3 and above--my TSH was 3.8 when I was having trouble conceiving (and many other symptoms). A year before that it was 3.4 and I was simply told it was "normal," even though I didn't feel normal then either.