Advice please

I need help. I'm 21, I live with my mom and I'm unemployed. I'm at a point where I feel like I cant function because even going to the store is so hard I cant do it without having someone with me. I feel like it's never going to get better. I have a history or suicide and self harm and I feel I'm reaching a dangerous point. I don't know how to talk to my mom. I know I need to tell someone and since she's the person I live with I figure she's the one I should tell. My family is full of people with mental health issues. My mom has depression and anxiety and my grandma on my dad's side has dealt with depression and suicide and all of that. My aunt also has depression and my older sister has anxiety. There are others but i dont want this to turn into a long list. It's so common in our family that it's almost like a joke to her I think. Like when I've tried talking about anxiety before it was basically just 'oh you're crazy like the rest of us haha' and there were promises of helping me get help but nothing ever came of them. I have brought up having suicidal thoughts before but it turned into her getting angry and going on about her own issues with those things and telling me I need to just power through it cause seeing someone might not help me. I know I'll need to take steps to help myself but I need someone there that will really support me and I need to get some kind of help. I do plan on figuring it out even if i don't have her help because I'm 21 and because it's been 4 years since I finished high school and I havent done anything. No jobs, no school, nothing and I can't keep living like this. I feel useless and worthless and having no job and not continuing my education makes it worse because I kind of am those things if I'm not doing anything. So I'm going to figure this out regardless but I would really like her help and support.