Help?

How do you cope with a friend getting pregnant on accident? Back story. My s.o. and I have been trying to get pregnant since the end of last year. 3 months ago I had a miscarriage. A few days ago a good friend sent me a text saying I'm going to be an aunt. My friend n my BIL have been dating for a month and she accidentally got pregnant shes about 6 weeks. I know it's really petty, but for some reason I feel so jealous and so hurt... Any advice on how to get over it?