I just need to let this out. I am sorry its long but i am really upset.

I am 24w2d pregnant with my first. And i am having my baby shower next Saturday (7/18) due to my mother being out of state for my older sisters birth of her second child when I'm further along. I really wanted to help plan/decorate/pay for the party and was told "no, you're an ungrateful bitch" by my mother .. Already nothing was started well, but I picked out my dress and everything. I have been finding little ways to get excited about it. I am having a very small party as my family sent the invites out a little late and a lot of family couldn't come due to other plans. I have no friends in the state either... When the invitations arrived my BIL and his girlfriend were really nasty about them. My BIL said "whoever sent out the invitations is a fucking retard" all because neither him nor his girlfriend realized to scroll down on babies r us to see our registry! I fixed that quickly by politely showing them. Now they were supposed to RSVP to my sister by the first. The day of I have my SO chasing them down and BIL like "who's going? I don't know anyone. I'll let you know". Finally at 10pm they tell us yes they're going. Which means 7 people are going because my fiance's parents and grandmother can now come too! My party will finally have some people and it will be a shared celebration of this little baby :). Today I mention to my SO's 9 year old niece that I am excited she will be there and can meet my nephews. She just looks me in the face and says "my dad says we are probably not going because he won't know anyone". So I call my fiancé who hangs up on me repeatedly because I was " listening to a dumb 9 year old". I reach out to my BIL and say I need a definite answer to which he tells me the same thing the little girl told me but with a massive attitude and trying to make me seem crazy. Now it's 8 days before my party and I have to tell my sister that the 7 people will not be coming. I am hysterically crying and just feel so heart broken. I told my fiance's niece she would have to tell my MIL and FIL they can no longer come because they will not have a ride. My fiance even caught an attitude with me and told me he will not be coming either. I feel really alone. This was supposed to be a nice thing for me and its not turning out that way.