Mommy dearest

Alicia
My mother begged and begged me and my fiancé to move into a big house with her and her boyfriend since we have a second baby on the way. After two months of debate, we decided to take a chance and take some time to save money.  
She showed us the house, we approved and got out of our lease at our apartment. The day before we're scheduled to move out, she lets us know that they didn't get the house, so while they continue to search, we will stay with them at their current house. 
While moving in, I find a rent receipt from their landlord... They're a month behind in rent!! ($1,350) behind in rent. 
My mom also informs me that when we get the house, they want to put the power bill in my name because they're -$800 on their bill... 
I feel like mother and her boyfriend completely took advantage of us because they're in a messed up situation. We already paid them rent for the month of October, because it was supposed to go towards move-in on a new house. I have no idea what she did with THAT money.... 
Every time I try to approach her about anything related to this, she blows me off and diverts the conversation. When I call her out for ignoring the situation, she just walks away and refuses to talk. 
What did I just get my family into! My fiancé works so hard to take care of us, and barely makes ends meet. And now my own mother is taking from us.  We have another baby on the way and she took away all stability that we had. 
I'm in a constant anxiety attack. I don't know what to do.