Feeling like a failure

I am so disappointed after getting my period today, cried and cried. Trying for a baby is so stressful, and I can't help but feel like a failure. It does not help that so many of our friends are pregnant (bragging about success on the first try as well.) 
I feel really alone and I don't really know who to talk to. So much pressure, and I feel like I've failed my husband. Mostly I'm just angry at myself...my body can't seem to do the one thing that it's supposed to be designed for. 
How do you all cope? Please remind me that I'm not alone here. Sometimes amongst everyone I know, I feel so useless, like I'm the only one who is having problems. Almost as if I don't meet some kind of standard. 
Please help. How do you find the strength not to give up?