It involves going to a doctor, which would involve leaving the house, which only happens with their knowledge and permission. Then, once that's done, it would involve going to a pharmacy, which, again, would only happens with their knowledge and permission. And it would involve either withdrawing money from my bank account or using my debit card, which I don't need permission for, but it's something they will know about, since it's attached to my parents' email address (The account was made when I was a kid and we didn't change the attached email later because my mum refused).
I say permission, but it's that way because I refuse to let the situation get to a point where I'm kicked out of the house. I could reasonably force my way out to get both a new prescription and more meds, but I'm not confident I'll be let back in. My parents aren't the most progressive when it comes to mental illnesses and its treatment. And I don't want to risk getting into a situation where I'll have to test whether I have any IRL friends at all.