/sad/ - Depressed

Hey peeps. There's this girl I met in 2009, she's been my bestest friend in the whole world since then. I liked her a lot, we were inseparable, close and just the most amazing of friends. In 2013 I had a very well paying warehouse job, she had finally moved out from her ex boyfriends place so I decided to take it upon myself to help her move into an apartment with her daughter. I payed her rent/bills, I put food on their table, I bought diapers for the little fuck. I also bought her a bunch of shit she didn't need. I bought her a 3DS so she could play with me, she asked if I could get her a phone instead so I got her both cause I was just that whipped. During this time I got her to like me back though, I was so happy I felt on top of the world. We even went on a date to a mall. Unfortunately this didn't last very long, I eventually lost my job and then we got into some toxic arguments that we never really recovered from. Towards the end of the year she left me completely. She moved back in with her parents and left me in the dust. In the beginning of 2014 she messaged me and I had resentment for her. But eventually we talked again and it seemed like I was gonna be able to get back with her. But then, something completely unexpected happened. She got together with this dude that she's known for two years longer than me, she didn't even want to date him at first she was just going with what her parents wanted at the time. She never ever told me about this dude until last year, never knew he existed or nothing. He has so much more to offer than I ever did even when I had my job. He's got a car, he's buff, he's way taller than me, I think he's even got a better job than I had. The year went by, I tried two relationships, the second girl she's engaged now to some fag in such a short time. Come November I heard my old bestie though, got engaged too. She'll be marrying next year. The weird thing is though they break up all the time. But anyways, she invited me to her pre-wedding party and I really don't want to go, but I haven't seen her in two years now. We talked recently and she let out her feelings to me, but then she went into a mode of back to the other dude. I don't really know how I got this to happen but anyways she really isn't giving me much of a leg to stand on. In fact a bit ago she even told me that last time she was single (recently) she rejected one of our mutual friends for me, but at the time (and I told her) I didn't want to annoy her and go all in because she had just broken up with that dude. I wanted to give her a bit of time to heal from that. I can't believe that was actually a golden opportunity. I beat myself up for it and she absolutely hates it when I do that. I know I know, that's so stupid. She literally told me something so crucial that I missed, how could I not beat myself up for that? Anyways, that's my story. I don't know what to do, I want to kill myself every day but I can't even do that cause she won't let me. She always tells me she doesn't want me dead. She really has me wrapped around her finger. I'm a slave to her and I can't move on or break free from this deep hold she has on me.