I think my mom needs help but she wont take it and everyone else is suffering

I'm 13 and I think my mom needs help
I'm a 13 year old girl and I make good grades and never get in trouble at school.
I suffer from depression and anxiety but if I tell her she just talks about herself saying how she's had worse and tried to kill herself instead of trying to help me I am extremely suicidal but I am not going to tell her because I know she won't care.
She only talks about herself and she always yells at everyone and everyone in my family thinks she is bipolar with depression and I try to tell her she needs to stop yelling at everyone and she goes off on me telling me how everyone wants her to move out and how I hate her and that we would all be happier if she died and I hate hearing that it makes me want to cry and I often do cry plus emotion is so awkward in my house so if I were to cry were people could hear it they would make fun of me.
She always tells me she doesn't care about me and how I should move out and I tell her about it and how no one should say that to there kid and she starts yelling at but then 5 minutes later she fine asking what we want from dinner.
Please help I always cry because of her I want my dad to divorce her so I can live with just him.
I always tell her how she is hurting me and she says that we always hurt her and that we hate her.
We always tell her to get help and she screams and says sure whatever but she will never help herself
My dad is usually on my side because he knows how crazy she is
About a month ago my family was going to fiesta Texas and she was mad because she said we didn't want her there and everyday she talked about not having money when she could be working anyways she ended up going but me my sister and my brother went ahead by like and hour or so and we were swimming in the park when my dad and my mom go there and she was mad because it was hot and she was screaming saying it was to hot and she is getting sunburnt and I got really mad and told her to leave then and she yelled until we finally left the park to go to the hotel and when we got to the hotel she was yelling about how this was the worst vacation ever and she wished she didn't come and my sister went off on her because my sister played for my mom and my dad to get into the park and she paid for the hotel my dad paid her back for the hotel and his and mine and my brothers tickets and she hasn't paid my sister back
She is always mad even when she went on a free vacation
She and I can't have a normal conversation without it turning into a screaming match
Please tell me how to cope or convince her go get help