What do I do, I need help or just someone to vent to

I lost the one person who tried helping me, more than anyone ever had in my life and it was my fault. I took her for granted and deeply regret it because of my stupid mistakes and the way id go about stuff. if I could go back I'd tell myself every regret I have when it comes to how I treated her. she was my best friend, the love of my life and dream come true for little me. a genuine soulmate to me and I lost it because I hurt her. and wouldn't put myself first. I wouldn't get the help I needed and lost it. now I'm losing myself more every time and I don't know what to do. I'm lost and the one thing I want is her guidance. I want her back in my life and to be here for me again. I want to show her I can change my ways and be the person she advocated and wanted me to be. I'm not some failure. I wanna be the person she loves. But that isn't possible because I wasn't a good person I wasn't who she needs/fell in love with and I just wish I was.