am i being unreasonable about my sister?

long post-

background: back in july i went into premature labor and delivered my baby boy at 21 weeks and a couple minutes after he passed. i'm 22, he was my first baby and i wanted so badly to be a mama. my water broke at 7:30am and he was delivered by 12:28pm. it was reasonably a very traumatic experience for me. i had no preparation, the day before i was planning on where to put his bassinet and the next day i'm having contractions, giving birth, watching my baby die, and having to decide whether he'd be cremated or buried. i'm honestly very f**ked up from it, i actively try not to let it destroy me everyday but the whole day replays in my head everyday. i've started therapy and am also on antidepressants.

i have two older sisters, one 31 and the other 29. i've always been closer to my oldest one because she was a mother figure to me since my parents worked a lot. i'm not close to my middle sister, i always had to share a room with her and she obviously hated it. i wanted to hang out with her all the time and she hated that as well. she was pretty mean to me growing up but just average older sister annoyed with little sister. after i gave birth and my baby died my oldest sister was absolutely crushed and called and checked in on me everyday. middle sister never did. both came with me to the funeral home to plan his cremation, while me and my fiancé were in my parents living room waited to go to the place my middle sister is walking in the living room doing spins in different dresses having my mom tell her what looks better. it had been 2 days since my baby died i'm literally wearing a t shirt and leggings with my hair thrown up. and she's doing a fashion show. i let it go and don't say anything. she's on her phone the whole time we're picking out his urn. we go to leave my parents and my oldest sister gives us a hug and my middle sister goes in the car. my oldest sister tells her she needs to tell me bye and give me a hug and she says "oh she'll be fine". i just found that part out a couple days ago and i've been fuming since. she hasn't called or texted a simple "how are you" the whole time. she also told my oldest sister that we aren't close because i never APOLOGIZED for tattling on her when i was younger. y'all she moved out at 17 i was TEN YEARS OLD when she moved out!! she literally told me she should've been an only child and she only loves her boyfriend not me when she was 14 so i was 7-8 years old. i've never once even thought she should apologize to me about anything she did because we were freaking kids? it was normal sister banter for the most part. i talked to my mom and she said that because my middle sister got out of a bad 8year relationship back in march (which she has since found a much better guy and moved in together) that she doesn't know how to properly display emotions. which i get i'm not expecting her to bawl and tell me she's so sorry. i did expect her to check on me a couple times. which i feel sending an "how are you" text isn't something hard. i told my mom that and said that honestly i'm done with her. i'm not going to say anything to her or start a fight but that i don't want to be around her anymore or speak to her. i went through a very very traumatic event and loss and i have people i don't even know checking in on me weekly via social media but my own sister can't once? i've never been one to cut out family but honestly it's just brought to light how little she cares about the situation that changed my life and has mentally destroyed me. i know she cares about me but i literally do not feel it because she's made zero effort to show it. the only time she did "check on me" was when my mom told her that it's upsetting that she hasn't and she LIED and said she has it's just not everyday. and my mom told her i showed her my phone and my sister literally has not sent one text or call since. (which i never wanted my mom to say anything to her about it i was just venting). she texted me once after my mom basically told her to and hasn't since. it was also 3 weeks after my baby died that she sent it. so because she's family she i keep her in my life? am i being unreasonable? i feel like i'm not but i'm obviously biased