Wishing, wishing and praying

I am terribly sorry if this brings anyone down but I have been going through a terrible time, espically the past couple of weeks. My husband and I have been trying to have another baby for about 4-5 years now and no luck. The doctors keep saying there is nothing wrong at all but, it seems as though no matter how hard we do or don't try we just cant get pregnant. Things have been really really hard lately because my sister in law and my other sister in law are both prego and wernt even trying and it seems as though every one i know is prego right now. It bites large!!! If anyone out there has any pointers please let me know. thanks