Hey Rosie87, welcome to the forums. Thanks for opening up to us.
Family conflict is always difficult, and having your anxiety and depression in the mix of it is extremely hard. I've never had a good relationship with my sister, similarly to you I have strong emotional reactions to conflict that triggers my depression.
I think despite the conflict right now.. the main priority needs to be your physical and mental health, which as you've described is effecting you greatly. I know it isn't easy to just distance yourself from the conflict.. but I think it would be more than worthwhile for you to focus on your own health first, and in turn you will be in a more stable position to mend things with your family at some point.
Have you ever received professional help for your anxiety and depression? Have you ever considered it, and are you open to the idea?
I think it's a great step that you've acknowledged that this is effecting you, and coming to the forums is a great place to start, I'm proud of you for that.
I hope you're taking care of yourself as best as you can, even in the smallest of ways.
We'd love to hear from you.