Please tell me I did the right thing. She was talking about harming herself.

I’ll start off and say my best friend who will be my maid of honor in September is 20 and I’m 18. She’s been having a hard time family wise lately from what Ive noticed. She hasn’t had a job in over 8 months after she quit her last one, she dropped out of college, and all she doesn’t is sit in her room all day watching YouTube and Netflix. (She lives with her parents). The only friend she has is me.

So tonight, we were going to get some Dutch brothers drinks and they were closed. We drove 30 minutes away so she was pissed! That was her breaking point after ranting about her parents pissing her off all day. She took her phone and threw it out the window in the parking lot. It ended up bouncing back and scratching her car. She started crying and said she didn’t want to talk to me or anyone right now. I let her be and she dropped me back off where I’m house sitting.

I texted her and asked if she was ok and she replied “no”. I kept telling her I’m here for her to talk to. She then showed up and knocked on the door. She had a diary of notes in her phone that dated all the way back to 2016 just saying how her life is shitty and everyone hates her. An entry from last month said she tried to commit suicide but then her mom showed up at home so she didn’t get to it. In a couple of her entries she wrote about how she’d been cutting herself. Her last entry was written tonight. She wrote how she stopped cutting but was going to try burning herself with a curling iron tonight. At the bottom she wrote that she “has a plan.” that she’s “going to go through with tonight”. She said that “no one will suspect a thing and they’ll all think that I’m sleeping”. She also said that she’s a waste of space and everyone always leaves her. (I move states away after my wedding day). I called my fiancé and explained everything to him. He said I should tell my mom so that she could talk to hers as I’m extremely afraid of her committing suicide. He keeps telling me I did the right thing but I feel as if I’ve broke her trust. I wouldn’t be able to forgive myself if I hadn’t have said something but I’m terrified she’s going to hate me because she asked me not to tell anyone. Did I do the right thing by having someone talk to her mom about it? Or should I have kept it to myself?