What do you make of this situation? ten points to some helpful advice.?

What would you make of this situation. My sister in-law to be has not spoken to me since we annouced our upcoming pregnancy. I am unsure if she is mad at me, or simply busy with wedding planning. She has completely ignored my phone calls and emails. A little background information on this, is she and my brother in-law were trying to have a baby since before my wedding last september she has suffered what i think may be two miscarriages. They already have one son who just turned 3. After miscarriage# 2 they decided to plan a wedding for august. We were pregnant before then and had wanted to wait a while to tell the family then we definately had to wait so we didn't steal their thunder of announcing a wedding date. Is she angry at me for being pregnant. stealing the thunder of her wedding time(she knew we were trying before they annouced the plans so technically i could pull the same crap). Am i wrong to be mad and annoyed as i have been nothing but supportive and excited for them. as i was when they accidently made their son and were not the most prime candidates for parents. And she is behaving in the most petty way. yet she has had the nerve to call mymother in-law and ask her to ask me if i have an address list for that side of the family. Why not call me herself. What would you do. should i confront her. i have received the invite for the shower from her bridesmaid and am having a hard time wanting to go pretend it is all nice between us when it is clearly not. i have done nothing wrong except start my family. i am angry that she would use that to put distance between us. She has said some really awful things about the family in general lately and i know she has made some negative comments about our baby to be. i want to let her know i am angry and hurt by these things. i am very close to my in-laws and attack on them bothers me. what would you do?