Middle child problems

This is the first time I ever tell this story, I have never told no one this story knowing that they would think I’m just overreacting. So, when I was born my mom had found out that my dad was cheating on her with another woman, she also found out that he had a child who was four years older than me. They ended up separating and for most of the time I was raised by mom, still communicating with my dad since his wife had also found out that he had another woman with a child. Few years later my mom decides to leave me at my dad’s for a few days since my older sister was having her Quinceanera, we went shopping for dresses and also decorated the house, then the next day, my sister went to get her hair and nails done while I was at home, playing with my two younger sisters, one being three years younger than me and the other being a newborn, after my sister was finished getting her hair and nails done we quickly get ready and the Quinceanera was going boring honestly, my sister had invited her friend over so she was busy, my dad was busy getting drunk and talking to his friends, so I had nothing to do, I walked around and even talked to people I didn’t know. Thats when time came, the time where my sister was going to dance with my dad, they start dancing and everyone around them start recording, then after they danced my dad reaches for a pair of heels and puts them on my sister, my eyes start getting teary, not because I was happy, but because I was jealous. my dad never paid attention to me, he would only pay attention to my other siblings, the only time he was truly proud of me was when I had good grades, of course my sisters had good grades, especially my older sister. Seeing my dad put one pair of heels on my sister broke my heart into tiny little pieces, not wanting to cry in front of many people I decide to just head towards my bedroom and sleep, honestly this isn’t the first time this had happened, this would happen almost every day, I decide it would be best I just ignore it since my dad wouldn’t care either way. I would also like to say that this event had happened years ago.