betrayed by family

I really thought the depression and anxiety I was suffering was getting better. Until my husband and i decided to adopt my pregnant 17 year old sisters baby.  Within a few hours of talking to her about adopting the baby she had talked to an aunt of ours, who knew we wanted to adopt this baby, and made the decision that our aunt Nissa would be adopting this baby. Now I can understand that she has the right to change her mind on giving us the baby, although I do feel like I have a few knifes left in my back from this whole situation. I dont think any one understands what I am going through or what they have done to me and my family. I have tried to talk to my mother time and time again to no avail. My mother is the one who told my aunt that my husband and I only wanted to adopt this child to do the family a favor, which we believe would be a very irresponsible thing to do in my husband and my minds. my mother keeps saying that no one knew that a decision was made. Although no one asked us if we had decided before just assuming that we had decided to adopt a child that we really wanted.  I really kind of feel like I am not respected as an adult or a parent even more so now then before. I confronted my mom today to ask her today if she even realizes that she hurt me very deeply by telling my aunt that we didn't really want this child other than to do my family a favor, my aunt didn't even care enough to check the facts. Today I told my sister that she couldn't talk to my mother on my phone. She responded by sending me a text message saying that: " what the fuck? I haven't done any thing to you. Stop acting like a twat." I really don't know how to respond that other than just walk away from it. When I do walk away from situations like that were there are no good ways to handle I am told that I am childish and I am trying really hard to be adult about a really hard situation. I was never really taught how to really act as an adult and I am now 23 years old and a mother of a two year old and I have one on the way and still trying to figure out on my own how to be an adult. My 24 year old husband is my best example of how to be an adult that i am around on a daily basis. My mother, sometimes, I believe acts more childish than I do. with her having a 17 year old pregnant daughter at home she can't really afford to be a child and I can't deal with her being childish still learning how to be an adult. When my mother starts to act childish it gets me very up set and puts me back in that mode were I just want to scream and act like a 12 year old and I don't like acting like that.