I'm so sorry that you're having a rough day. It took us 7 months to get pregnant with DS- and while I know that 7 months is not very long to TTC, it sure felt like a long time.
Like the pp said, check out the helpful info from the Trying to Get Pregnant board.
Are you charting? Maybe you're not trying on the right days.
Good luck. I really hope it happens for you soon.