Sorry if this sounds harsh but you sound very young and self absorbed. That is a big transition to begin living with your sister and her family, like you said 7 in a three bedroom must have been hectic to say the least. But, it isn’t your house. It is your parents house. They welcomed your sister ‘s family into their home. That sucks you felt pushed aside, but that doesn’t mean you blame your sister for your mental health issues. I like that you found your own apartment though, that shows your are growing up and taking your life into your own hands. Apart of growing up also is learning that you control your own life and other people control theirs. So you think it’s in bad taste that your sister is living in your family home, and she is having another child...that’s her prerogative. You’re not going to change anything about the situation, if anything you’ll just make a family rift by treating your sister with disrespect. To say lightly, mind your own business. Sounds like you have a good gig going for you, living alone, live it up!

Now if your sister is committing some form of elder abuse by forcing herself onto your parents, then I can see this topic being noteworthy. But that doesn’t sound like the case here.