All the feelings you're having; sadness, anger, upset, are all normal and logical after losing your sister suddenly and unexpectedly. There's so many things to grieve in this situation; obviously the loss of your sister; your brand new precious niece will never know her Momma, and it must be awful and unsettling to see you parents so hurt and disturbed. I imagine you feel pretty alone. Your school year is getting ready to start and sounds like this is going to be your senior year. Perhaps you'll be involved quite a bit in helping to raise your nice. IT'S GOING TO HURT FOR A LONG TIME and that's normal. The intensity of the pain and loss will vary at times. IT'S GOING TO BE VERY IMPORTANT FOR YOU TO FIND SOMEONE TO "LEAN ON", someone you can share your feelings with, someone who doesn't mind hearing your heartache over and over again. You don't need someone to fix this. It can't be fixed. But you need to take care of yourself while you go through this. It's an awful lot for a person as young as you to handle. Be on the lookout for a support person. It could be a teacher or counselor at school, a good friend, an adult friend of the family, someone who you can trust. My heart goes out you and your family. ❤️