(17m) I'm in a 11 month relationship, How do I breakup with a suicidal girlfriend.

I want to breakup with her because me and her are different people kind of in a way

Her home life is harder then most. Her mom struggles financial in result she's usually has more freedom then me but is alone most of the time which makes her depressed,negative towards herself and suicidal. She also smokes its not a occasional smoke or for fun, she uses weed as a crutch to hide her feels which only brings her down more she usually smokes by herself 3-4 times a day.

I am a senior In High school and have now started looking at my life differently basically what I need to do next how I need to stay out of trouble and be grateful of my parents and what I have. One of those things is telling my parents the truth and not doing things behind there back. I feel like she is bring my down instead of allowing me to go forward. I care about her a lot and the last think I want is to hurt herself but like it would be best if we breakup and go or separate ways.She is REALLY emotional and gets really depressed over little things.

As I'm writing this I feel like what I really mean is I think I can find someone better for me and that I got too deep in a relationship without thinking about it

TL;DR In a 11 month relationship with someone who is often depressed and negative