Tired of Feeling Depressed

Last November I had a miscarriage and it's been almost 7 months but I haven't been able to get pregnant again. I don't have any children and I just feel like a failure. I'm so ready to be a mom. I'm so tired of watching everyone around me get pregnant. When does it get to be my turn? I'm sorry for complaining but I figured this was the best place to express my feelings. I've always had depression, but after this miscarriage it just keeps getting worse.