I'm so depressed.

Me and my SO have been trying to conceive for 9 months, I had a miscarriage in February and we kinda quit trying but we still have high hopes. I for the life of me can't conceive and I don't know why. My SO smokes weed daily but that won't affect anything if people who smoke crack can conceive. Its not fair we want one so bad but no luck at all. Am I broken? Its so depressing and wondering why me? I'd be a amazing mother. Its not fair..