Found out my sister is pregnant this morning!

I know it’s awful, but I’ve been TTC for over three years & I just found out this morning my sister is pregnant… Again! She had my niece very young, 13 years later she is now expecting again and I can’t seem to get pregnant. The awful part is how jealous I am, I am so happy for them, I just wonder why not me? They were trying themselves, I am super excited to be an aunt again… My friend told me yesterday, you won’t be a mom. It hurt more than I think she realized, she said she just didn’t see it in my future or me. I pray she is wrong, I don’t know what to do anymore but I won’t give up!