Not sure which page . My daughter s anger

I'm not sure what page to put this on. My 18 year old has serious issues with anger. Let me start this with a lot of truth. I was an abused child growing up. I am married with two daughters 18 and 20. I have been very negative, abusive and mean natured as well as loving and giving( if you can believe it) I love my kids very much. I Aam a very moody person and very well know my actions have caused this with my daughter.
My daughter growing up has always been the mommas girl. Very attached and I have had a hard time doing things without her. Until her teen years. Now she hates me around her but then gets scared if
I am not around. It's odd. Anyway she seems to get angry every single day and when something sets her off she has a hard time shaking off the mood for hours. She tells me and my husband and her sister she hates us on a daily basis. She's 18 but acts 15. She is no where near adulthood. I know I get that it's my fault.
Today she went to a theme park with her sister and her two cousins age5 and 11. The 11 year old kept instigating her and hitting her and finally my daughter yelled at her and swore at her ( she ones not swear so my older daughter was shocked) , then claims she snapped out of it and said sorry right away and said she didn't realize she had sad it. Said he got so mad she blacked it out. My older daughter said the way she swore and how it sounded wasn't how she normally speaks. She came home to talk o me about it because she was scared. My 18 year old said she gets so mad sometimes he lacks out nd ones not remember what she's saying. She feels badly about it afterward.
Another example : she got her period at work and drove all the way home completely irate and wanted to quit her job because they didnt rush over to I've her a bathroom break. She got blood on her nderwear( I saw it and it was spotting) she acted like she was bleeding to death. She came home and changed nd stayed in a horrible mood at work texting me hundred times that she wasgoing to quit and she hated everyone. She opulent shake off the mood or act normal. There are a lot of other examples too. When she walks to bathroom from her room and I say hi she angrily says hi back. She will go to bed at 11 at night and sleep until 1 the next afternoon. 14 hours of sleep. If anyone makes her angry he says she's going to hit veryone( she never has) tells us to kill ourselves. Tells us our voices are annoying. Tells everyone in the house how she hates us. Then tellsus she really doesn't mean it and she loves us. I'm not sure what to do. Before anyone says anything about her being 18. She really doesn't act 18. She acts years younger. She was in lower level classes in school because sh was slower than other kids at getting assignments done. Wasn't good t math and got frustrated with any work at school she had to do. Teachers in 9th grade thought she may have add but I didn't want her zombied out on medication. She fit in with the kids who had learning disabilities but wanted to be part of the popular crowd. School was a huge struggle. She never wanted to complete any assignments on time. I pushed and pushed her to always do one work and keep up on school work. She liked having easy classes if it meant doing the least amount if work. I need help. I want her to be okay. I don't want her to be mad all the time and hate to wake up. What can I do??

I typed this on an iPad in middle of the night. Sorry there are a lot of spelling errors.

I do understand, when my brother we young he used to hit his head with the wall after being angry. We were too much horrified thinking that he might have weakness to suicide. We had lot of counseling and finally but gradually he become fine. Still we can observe a bit more aggressiveness in him that the normal man. I guess your daughter need a good friend who can understand her well and keep much time with her in every situation and decision taking mater.