why won't it happen

me and my husband have been trying to conceive for nearly a year now, had to take a little break for our wedding but got back on it as soon as it was over but doesn't seem to be working and it's getting me down to see all my pregnant friends around or when another pops up saying they are pregnant, my worst fear is that I won't be able to get pregnant!I'm getting so depressed about this that I just sit and cry on my own, i just don't no what to do?!