Girls, hello! Could you please tell me why I'm not getting pregnant?

Girls, hello! Could you please tell me why I'm not getting pregnant? Our tests are all in order, I catch ovulation with tests, we seem to be getting there... but pregnancy isn't happening. Yes, it's still been a year. But why then can't we get it going? ?? I get really upset when my period comes. We really want and wait for a baby, but it's not working ? I read on posts that you need to let go of this situation and forget about it...but how do you do that? I still think about it periodically.