I'm slowly starting to hate my best friend... advice?!

So I'm in my sophomore year of college, second semester and I'm rooming with my best friend and I'm slowly starting to hate her.. She has always been a good friend to me and is there when I need her, I can trust her with secrets and she is loyal. The thing is we are exact opposites and I'm not so sure we would be best friends if she wasn't just the first person I clicked with when coming to college.
She is extremely shallow and only cares about improving her looks and judges others. She is the kind of girl who scrolls through instagram just saying "this girl is NOT pretty" or "she is so weird looking" or "she is too fat to wear that". And I never know what to say because I don't think it's right to talk negatively about the way people look, they can't control that.
She is the most negative person I've ever met. Recently, this past year I've had a revelation or epiphany on how I want my life to be. I've decided to always be kind to people and always be positive and just BE happy. It honestly has done wonders for me. But she constantly brings me down. She is so dramatic and gets upset SO often. I've learned that not everything NEEDS a reaction. To her, everything has an overreaction. She constantly talks shit on girls that I like and says they're a bitch or something and I don't know what to say. She complains every single day about something new and usually it has to do with her parents not doing anything for her, which is stupid because they literally HAND everything to her. She doesn't have a job or anything.
Lastly, I really and truly think that she thinks my world revolves around her. I have my own life. She is my best friend and I want her to be in it. But she is not my ENTIRE life. If she asks me to get dinner and I say "oh I'm actually getting dinner with Ashley" she will text back "ugh okay whatever". Recently I started dating this guy I REALLY like (different than any guy I've dated in the past). His name is "Ryan". I rarely hangout with Ryan on the weekdays because we have classes and other stuff but on the weekends I'm usually with him. She literally gets mad at me. She makes comments like "you're forgetting about me" or "you are with him all the time" and says it in a way that I know she's trying to make me feel bad about. I know the concept of "don't ditch your best friend for your boyfriend" and I can 100% assure anyone that I am not doing that. She is my ROOMMATE, I'm with her almost all the time. But she can't stand to be alone. If i tell her I'm gonna hangout with Ryan for the day she will literally say "wow now i'm gonna be all alone what am i supposed to do?" and it makes me feel bad but my life does not revolve around making sure she is happy and okay and not alone but that is what it recently has started to feel like.
She is a very insecure person and i know that ties into a lot of why she is the way she is. Her whole life her mom always made comments about her not being pretty enough or needing to lose weight (she is literally one of the prettiest looking girls I know). So I think that's why she is shallow. She is not a happy person at all. And she is so insecure she can NEVER be alone. She doesn't even like going to the library alone or something and I am that person that she always expects to always be with her when I have my life too.
I want my life to contain nothing but positivity. I literally notice a change in my happiness when I don't hangout with her and I hangout with others who are happy/ kind people.
We are talking about being roommates again for our junior year but I don't know if i can do it.
SHOULD I SLOWLY DROP HER AS A FRIEND? (VOTE YES)
I've always heard advice and quotes about coming to a time in your life where you need to be selfish and think of your happiness and only include people in your life that make it positive and benefit you and your happiness, and to drop anyone else. It's supposed to just make you a 100% percent more happy person. If i dropped her, I wouldn't want to call her out and tell her I never want to be friends I think I would just slowly stop hanging out with her. I would make an excuse as to why I can't be her roommate and then next year I just would slowly stop giving her all my attention.
SHOULD I KEEP HER IN MY LIFE AND TRY AND MAKE HER HAPPIER/ KIND? (VOTE NO)
On the opposite end, should I stay in her life to try and improve HER life? Sometimes when she talks shit on people I stand up for them and sometimes she notices so maybe she will eventually stop gossiping. I'm constantly giving her advice on how to make herself happy and how happiness starts from being happy with oneself. I also think I would call her out on how she is a big part of my life and I want her in it but my entire life isn't just going to involve only her.