Am I wrong?

So, this is going to be a long post and I apologize but thank you in advance to those who have read this and taken the time to respond.

Things have been rough for me for a long time. I guess you could say I have been a people pleaser, or I am a giant push over, or both. But, I lost my job last November and haven't been able to get one since. Not without lack of trying. I have always been a hard worker and I honestly prefer working than sitting at home any day.

When I lost my job, I was living with my sister. We signed a one year lease together for an apartment and had worked really hard to get it. During this time, I always tried to make sure my sister had everything she needed. When she needed help with her personal bills, I helped more times than I can count. Although the reason she couldn't pay them herself is because she didn't manage her money well. That's not the point, though. I made sure she had everything she needed. No matter how awful she treated me. I even went as far as signing her boyfriends bail bondsman witness forms to get him out of jail for her.

Fast forward. Her boyfriend is a drunk, verbally abusive piece of shit. She and him kicked me out one month after I lost my job because I couldn't contribute. When I asked her why couldn't her boyfriend help with bills, she said "it wasn't his place to pay bills" even though he lived with us, he is on probation and he put our address as his address. So, I stayed with my boyfriends family for about 6 months.

Fast forward again. Some things happened and I just couldn't take living with his family anymore. My sister was weeks away from having her son at the time, so I figured she may need help here and there. My boyfriend and I eventually moved in.

Now that my nephew is just over a month old now, so many things have went wrong. I am automatically expected to watch him whenever she doesn't feel like it. She hates taking him with her places when she leaves the house, so she guilts me into watching him when she wants to leave. She allows her bastard boyfriend to drunkenly scream at her in front of him. Has the nerve to ask me to watch him while her and her scumbag boyfriend go in the other room to have sex. When I do agree to watch him while she is gone, she tells me she will be back at a certain time, but I end up watching him for hours.

I can't take it anymore. I have been trying to deal with this until I get a job so I can get away from it, but it is so fucking hard. She makes it so hard on me. All the while, I am expected to let her stupid fucking boyfriend try to demean and dominate me. When I try to tell her that she has to eventually get comfortable with taking her son places, she makes me feel horrible. Just tonight, she told me that she didn't want to take her son with her to go pick up her boyfriend from work, and I calmly tried to tell her that just because her son is asleep doesn't mean you get a free pass on pawning him off on someone. She then threw everything in my face, saying how much she does for me, this and that. And I lost it. I never tell her how I feel about how she treats me and how she treats her son, because I hate confrontation. I told her that it was fucked up for her to throw that stuff in my face. Just to clarify, I never said I wouldn't watch her son. Her friend Kevin was over at the time, and to be spiteful she said, "Kevin will watch him, don't worry about it." without even asking him first. She just doesn't care. She doesn't want to fully deal with her child. What is she going to do when she doesn't have anyone to watch the baby and she has to go somewhere?? She doesn't want to deal with the fact that her child may cry while out in public, but that's what happens when you have a baby!!

I'm sorry this is so long. I don't know how to deal with this anymore. Her boyfriend gets drunk and screams and yells all day, even while the baby is sleeping. He tries to intimidate me frequently. I am expected to not instigate him, or basically stand up for myself. She is constantly trying to pawn her baby on me, and most of the time the reasons aren't justified. Don't get me wrong, I love that baby to death but I just wish she would do right by him. He deserves better. I don't mind watching him when the reasons are justified. I do mind watching him when she just doesn't want to deal with him. I understand that you need a break from time to time but lots of mothers never get that break. She is never appreciative of what I do. Never says thank you for anything.

I feel like this needs to be said. Almost a month ago she found out that her boyfriend cheated on her. When this happened, I watched and took care of my nephew for five hours because she "couldn't look at him" after finding out what her boyfriend did. She couldn't even look at her baby for something her boyfriend did! For five hours!!!! That isn't the child's fault. That is just an example of how she treats her own child sometimes, and she doesn't even realize it I don't think. I am 19 and she is 26. I need to focus most of my energy towards getting my life together and I can't do that because of this situation. All of this has taken a toll on my mental health. It seems like I don't have time mend myself because I am obligated to worry about these things that I should not be worried about.

Before anyone says anything, I don't have anywhere else to go. No friends to stay with, no family. If I did, I would've been long gone. I've been trying to stick it out until I got a job. Looks like I won't be able to wait that long. I guess what I'm wondering is if I am in the wrong for feeling the way I do? Is she doing right by her child and am I just being difficult? I'm not sure anymore. Please help me clear my head about this.

Thank you.