Need some encouragement

Brittany
I am 26 years old and have been married for 3 years, with my husband for almost 9. 
We have been through so many trials and struggles together and always come out on top so in December of last year, we decided to try for a baby. 
I am having zero luck and am starting to get extremely discouraged. People come up to me and ask me all the time when I am going to give my parents a grand baby and the only thing I can think about is screaming at them I am trying my best. 
I was so positive until now. I kept saying "next month is a better month anyway," but I am finding it hard to believe that anymore. 
I ask myself all the time what is wrong with me. Why can't I get pregnant when so many others can. I feel like my heart is breaking every month when AF shows up and I don't know if I can keep going. 
Can anyone share their positive stories? I want a baby so much, and I know some may think I am prematurely getting upset but I have waited a while for my husband to get on board with me having a baby and I always assumed I would have one right away when I was ready :(