Addiction has taken over

I am the only one in my family without an addiction. Drugs? I can put it all down. I’ve experimented, never had a problem setting it down. I was born to meth head parents, my mom has maintained her sobriety for years but my dad falls off and on. My problem is that I think it’s a choice. They all choose to cope with life that way. I dont. I used to play around and smoke snort and pop pills but it was never excessive when I think about it. I’m here because my sister is a serious addict she is working her program and is one month sober. She still has psychotic outbursts that stress me out. Watching her threaten to kill herself and run away is awful. I just dont know what to do. We disagree heavily cause I think she chose that life. I also dont like how my parents just baby her and trust her so quickly. I drank a couple beers on a camping trip with my friends family when I was my sisters age and I was grounded. I dont get how someone who can be doing meth cocaine molly xanax weed you name it she does it and my parents treat her like some god send angel. I’m the black sheep who’s a heartless ***** in the family. Got the label of toxic. Smh. Sometimes I wanna start drinking again and popping pills again just so I can feel the way she does sometimes chase after the rush she felt that I personally haven’t felt in a while. Watching her struggle makes me wanna go down a dark path so I’m not that “sober *****” anymore.