My sister is self centered

I have an anxiety disorder and so does one of my two sisters. My third sister, who is the middle sister, has been giving me hell for the last year. She snaps quickly and recovers fast, which upsets me a lot. I really struggle to balance other people's emotions and I've tried to discuss with her and tell her that we need to find a way to communicate that doesn't give me panic attacks and ruin my day or week. I feel like I was very calm and wasn't blaming her but trying to work together, but she immediately bursts into tears when I talk to her about it and acts like I'm bullying her when she gets away with messing with my mental health especially because I have been trying new meds for the last year and have needed support. This fall one of my brothers developed anxiety and depression and almost attempted suicide which was very traumatic for my family, and my brother had resorted to drugs to deal with his illness even though he has all the access to counseling and meds that I did. My sister has only gotten worse since this fall, she continues to take out her stress on me and refuses to even discuss working out a solution. With all of our family stress over my brother, my middle sister hasn't stepped up at all to help with even basic stuff like getting foot for our house, she even struggles to do anything on her own. She is constantly calling my mom and when she is stressed she creates a meltdown and brings everybody down with her. I feel very stressed out, I'm still trying to work on my anxiety but my house is so stressful and I never know when people are going to have meltdowns and I wish I had more stability. My house doesn't feel like my home anymore and spending time there makes me want to crawl out of my skin. I just wish my family would put more effort into fixing their own problems instead of bringing everybody into them.