How do I cope with always feeling like the runt of my family litter?

I’ve been feeling really upset and overwhelmed with my family lately. There’s a long-standing pattern where I often feel left out, dismissed, or treated differently compared to my sisters.

Things have been building up over time, especially around my sister’s pregnancy, as I’ve felt excluded and like there’s been a bit of dishonesty and cliquey behaviour in the family as she's chosen to tell everyone in the family but me but I found out by accident. Her excuse is but ill tell everyone and put it on fb. Firstly I dont use fb that often and I don’t see anyone who knows her enough to tell them plus the people in my life don't know her nor would care.

I also feel like when I try to make jokes or speak up, I get put down or made to feel like I’m overreacting, even though it’s upsetting me. It’s got to the point where I’m questioning whether I want more distance from them because it’s affecting my peace of mind, especially while I’m pregnant.
I don’t want drama, I just feel hurt and misunderstood and I’m trying to figure out how to handle it all.

I often feel as if she's jealous of me because I got everything she wanted first and thinks I don't deserve it because im not as amazing as she thinks she is.

I wanted to cry today at my parents but I kept it in because I knew I'd be made the issue as I always am for simply having feelings and expressing them but I constantly have to protect everyone else's feelings.

I think my mum and dad actually see how bad i get treated but chose to ignore it as im the youngest child there for im basically just the one that was meant to be a boy so I dont really matter and im never gonna be good enough for them.

My stister is very successful too and id say her and my husband are on equal levels of success but whenever I celebrate my family's success my family shame me and act as if I think im better then them for it or flashy but if im stister celebrates her success its like she shits golden eggs
Updates
3 mo
I was really excited for her when I first found out and wanted to support her and for are babies to be best friends but she's clearly made her choice. I feel my baby will be treated the same as I have too now and what makes it more fucked up is i was the first to think she was pregnant and tell her to take a test and my whole family already knew and she lied and dropped hints to me to mislead me
How do I cope with always feeling like the runt of my family litter?
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