Dealing with an ignorant/ableist sister

I (16F) have always had a not-so-great relationship with my sister (19) and ever since I was diagnosed it’s only gotten worse. When I got a shower chair she went on a rant about how impractical and ugly it is and how she wants it out of the bathroom anytime I’m done with it.

I had a bad flare up one time in a restaurant and needed to sit with my legs up (I sat on my jacket so it’s not like I had my shoes on the couch) and she said that I should be ashamed of myself and that other people will find us weird.

She also really likes to give me unsolicited advice and said I’m ungrateful when I asked her to stop. It’s always something like "I also get tired sometimes but I still do stuff" or "just eat more"

I’m barely completing school rn and she really wants me to have a job. I had a discussion about it with her and she kept saying that I just need to try and when I told her that I’ll either get fired in a month or quit after a week she was like why are you so negative. Girl I always miss a minimum of two days of school per week how do you expect me to work a job on top of that