My good friend won't forgive me?

I've been friends with this girl for over 8 yrs. She is/was my bff. We went to different schools though last year. We still talked. In January I was diagnosed with depression. Depression has caused me to do things I wouldn't do if I was happy. My friend can't understand why im doing these things. She doesn't believe I'm depressed. She wants me to listen to her but I don't really listen to anyone. I feel like she doesn't even care. People change and I'm going through a rough time. How can I get her to understand that? I've tried telling her I'm not really sane:/