Am I overacting?

I know this isn’t the right platform but I just need to rant because I have no one else to talk about it because then I’m told “I’m crazy”. I don’t necessarily need anyone to reply I just need to get it off my chest.

So I still live at home with my family, I’ve got a younger brother and ever since he’s turned 18 I’ve just noticed he has no respect or anything for me or my parents he goes out as long as he wants even when my parents give him a curfew and he just gets away with so much stuff that I would never ever have.

Anyways lately whenever he is home and not out with his friends when my mum says anything to him just general chit chat and I join in he just bites my head off and tells me to mind my own business. And I’m just like woah what the hell

But tonight just got to me. My family and I were having dinner, and my mum is having a conversation with him and I just agreed with her.

And he absolutely cracked it at me and that was the last straw because I was over being blasted for just speaking. I said to him “wtf is up with you, you constantly go off at me when all I’m doing is having family conversations, you all of a sudden have this attitude with me for no reason” he then barks up and says “I wasn’t talking to you so mind your own business”. I just got pissed off and he starts laughing at me and starts egging me on. I just ignore him. Then after dinner my youngest brother hides my other brothers phone and then of course my brother gets pissed and thinks it’s me I tell him it’s not and he sees my phone on the table and takes it. I tell him to give it back and he’s like not until my other brother tells him where it is. I get mad and get my phone back. Then my mum tells me I’m overreacting and carrying on and I’m just like wtf he just took my phone for no reason. Then I hear my mum talking to my brother and he’s talking shit about me getting involved in conversations and I turn around and I’m like “we were having a family dinner and all talking to each other and you cracked it at me. Ever since you’ve been hanging around your friends you’ve been so rude to me and acted like I’m not even your sister” he starts laughing again and “goes see see you’re getting involved again you’re just mad because you have no friends”. He then goes on to call me names and my mum doesn’t say anything. I walk off and get so mad I just can’t help but cry. Later on, I bring it up with my mum and she goes on to say I went overboard and sides with my brother. I just start crying again out of frustration and she’s like are you seriously crying like why. I walk out of the room to get a breather and then she walks in being all lovey dovey asking me what’s wrong and why I’m mad at her

I’m just sick and tired of being practically gaslighted and then called crazy and my mum taking my brother’s side.