Hello everyone I am new here but wanted to sign up because I desperately need help with my ste daughter. I'll give a brief background of her and what's going on. Please understand that I'm very frustrated, angry, and emotionally exhausted by her so some things I say might come out not so politically correct. I'm not a bad person I'm just fed up with her behaviour and need an outlet to vent and also some help and guidance from others. 
 

She is 6 years old. I got together with her dad 2 years ago when she was 4. She lived primarily with her mother who at that point was a recovering alcoholic, had been jailed and admitted to psych multiple times for alcohol induced psychosis. We would have her for about 7-10 days a month as my bf worked out of town, 2 weeks on/off. At this time her mom had been sober for 16 months and all was well. Altho I will note she was spoiled badly by her dad, probably his way of compensating for lost time. She had no bed time. She ruled the house. Had no manners, no rules or structure when she was with us. It being such a new relationship I felt I couldn't step in and make suggestions. He was completely blind to her bratty snotty behaviour. Fast forward to January 2020 I became pregnant. In April we move in to a new beautiful home. At the same time I have to go off work because I had hyperemesis - severe morning sickness al day and night and could not continue to work. Almost at the exact same time her mother fell off the wagon. We got a call from social services saying they don't know where she is. We track her down and I go pick her up. From that point she's now living with us and her mom eventually has visitation. Her mom was admitted to psych roughly 3 times for more induced psychosis episodes. Then in June her mother dies of an overdose - we are still not sure if it was accidental or not. We get the whole family together to break the news to her and shower her with support and love. We enrolled her in school here and things were going pretty good. Fast forward to sept 2020 the birth of my son. And her behaviour has been deteriorating since. So what I'm dealing with now is the worst behaviour I have ever seen from a child. Yes I know the reason for the behaviour but it doesn't make it easy to live with and it doesn't make it okay either.

She is: peeing her pants on purpose day and night. She has hurt my son 4 times, pinching, putting her full weight on his chest and lastly tried to stick a pointy object into his eye. I was trying to sleep train him but no longer I want him to sleep in his room because she honestly scares me. She is defiant and manipulative and there are times where I feel a frightening darkness in her. Two of my close friends independently picked up on this as well without my mentioning it prior to them. She is starting and getting in to fights at school. She is rude to, and has no respect for, authority at school. She is mean to her friends to the point where they no longer want to play with her. She's very jealous that she is no longer the star of the house, or I should say - the only star of the house. We honestly give her tons of attention and have made a point of that since the birth of my son. She has absolutely no respect for rules. 
I understand she is grieving.. but why are all these issues happening now and not when her mother died? 
I'm sorry but I've f***ing HAD IT with her. I don't want to see or hear her. I can't f***ing stand her anymore. There is nothing good about her anymore, it's all negative. The house is no longer a nice place to be. I don't want this to rub off onto my son and I hate that he's being raised in such chaos. I'm doing my best, but I'm getting to the point where I just hate her. I know that's a horrible thing to feel and to say but you have to understand that this is CONSTANT. She is CONSTANTLY doing something bad. CONSTANTLY bad attitude. CONSTANTLY whining and complaining. There's no breaks with her. It's all bad. I'm trying to do my best with her, I'm never mean, never yell but I feel like I'm going to lose my mind. 
She's started counselling - everything was down due to covid in our area. 
As for the peeing herself I have started to make her wash her underwear and pants by hand. And am going to start having her wash her dirty sheets (put in laundry machine herself). I'm on the fence about making her wear diapers because that'll only give more attention. But at the same time she's absolutely trashing her mattress. 
 

please someone give me some guidance. Please don't judge me.