How do I keep up a good face?

I had a miscarrage 2 months ago. The doctor said it was ok for us to try again after I stopped bleeding, but we aren't having any luck. No one knows other than my husband and I want it to stay thst way. Anyway, my sister-n-law announced thst she is 9 weeks pregnant tonight. (I was 9 weeks when we lost the baby) I feel guilty that im mad at her. How do I get over this feeling?