How do I convince my parents to get me another dog?

I already have a dog but she s very mean and constantly tries to bite me and growls all the time. My Mom says no because the dog we have now loves her and follows her around because she s "the alpha". The dog we have was supposed to be mine and we got her 7 years ago, but she simply despises me and it s just not a good arrangement. I also have many mental health issues and I ve read that if you get a dog that is very friendly it can really help with mental health. I was thinking about a Labrador retriever or a Golden retriever, but my parent s excuse is that we already have a dog even though they know the dog we currently have is awful. So please, does anyone have any tips that could help me? I m out of ideas and my anxiety has just continued to increase please help.