Feeling overwhelmed: need advice


So i don’t really like telling my businesses but my heart hurts so bad rn and i have no one to talk to.

I’ll try to make this as short as possible

I’ve been with my bf for 2 years now and this is the 3rd time i honestly feel like he just doesn’t have my back I’m all for the truth wrong is wrong and right is right so please fell free to be honest with me.

Last night i found out my little sister is pregnant my her bf of 4 months who disrespect her and cheats on her with makes me upset but that’s her choice. So anyways I’m having a conversation with them while my bf went to the store and I’m trying them I’ll help out as much as i can but they really have to step up and he needs to get a job and help her ( both our 18) as I’m saying this her bf says “I’m sorry i didn’t know you were my mom”

I than said I’m not trying to be your mom I’m trying to make sure you guys know that you have to work together as a team it’s not about you guys anymore you can’t be selfish this is life that your bringing into this world” he than gets in my face and says “yeah but did you lay in the bed and make the baby no so why are you worried “ i got mad and that’s my little sister I’m always gonna to worry about her and you don’t have anything remember that’s why your in my house now “.

My bf walks in the door and asked why everyone was quiet as he’s walking in the kitchen I walk with him to go make his plate and tell me what was said and before i get everything out her bf is standing right next to my bf telling him I’m crazy and weird.my bf looks at me and tells to stop telling them to be on their ps&qs. I told him how am I’m telling them again when u asked what happened? So than we ended up fighting.

I say this is the 3rd time he didn’t have my back because before he’s done similar . And in between the mist of us he called me to my sisters boyfriend and he was not picking And in between the midst of us ready he called me to my sisters boyfriend and he was not picking sides.

Now me i feel your my bf you should be on my side now if I’m wrong pull me to the side and tell me as i would.

Do you guys think I’m over reacting??? Because I’m really upset he didn’t have my back her bf called me a bitch in my own house and my sister and bf both told me to claim down i don’t understand