@anita:

I wish you had a separate room from your sister. Maybe it would be better if you slept on the sofa, in a common area of the home, instead of in the room with your sister (“we are in the same room 24/7“).

I don’t feel comfortable sleeping in the sofa because it’s really small and parents come out randomly at night

not a good automatic reaction or behavior. No wonder she prefers to be  online with friends instead of listening to your rants. Find a way to change this behavior from being automatic to being a matter of choice (no matter how hard it will be). Choose to not rant and vent. Instead, you can journal, draw or post here, or go elsewhere in the home.

I try not to rant to her about everything. Instead, I try my best to keep it to myself. And she always rants to me too.

imagine that you are outside your home, interacting with a person, and notice: are you having eye contact with the person, or are you looking away? Are you smiling at them or is there a frown on your face? When you talk to them, is your voice gentle or harsh? You can stand in front of the mirror as you imagine these things and look at your face: what does it communicate?

People often say I’m soft spoken and quiet in person.