I should be happy but....

So i have been ttc for almost 5 years now. My brother who hasnt been trying at all, just found out his gf is about 7 weeks along. I should be happy for him. But im not. Im utterly jealous. I feel hurt and betrayed by my own body for not being able to have children. To make things worse i live with my grandmother to help her out around the house and shes soo excited and bragging to everyone and asked me, knowing full well ive been ttc for the past 5 years, "now its ur turn. When r u going to have kids?" :( i just feel like giving up.