Scared of xanax

Im a 20 years old from italy, i've been suffering from unidentified mental illness for the past 7-8 years and never got a proper diagnosis. It's mainly about depression, but includes anxiety, sociophobia, eating disorders and a bit of ocd and other stuff. I get addicted really easily to literally anything, from drugs to doing things like stealing, cutting etc I've been on zoloft for the past two years but since lately anxiety is kicking my ass my psychiatrist decided to give me xanax as well. I've already been abusing zoloft (as "study aid" since it keeps me awake) and other stuff and i KNOW it'll happen with xanax too but my doctor said she trusts me and i'll be fine. I've always trusted her, she's the only one with whom i had at least a little improvement, but now i'm not sure anymore. I tried to explain this to her but of course she's the doctor and she knows better than me whats good for my mental health. I live alone, i've no one controlling me to make sure i don't overdose. Even if this happened just yesterday and i still have to buy it, i've already been googling xanax lethality and its recreational use and this kind of stuff, "just in case i'll need it someday". I'm scared, I don't trust myself and i know that even if now i'm pretty stable and kind of fine i always have big crisis every now and then and in those moments anything could happen. Anyone else in a similar situation? How do i deal with this?