I suffered from depression for years. I cut a lot of people out of my life and the people that were still in my life did their best to destroy me even more. I felt so alone. I wanted to die so many times. I got into drugs. My degree was suffering immensely. Any chance of a future career was suffering immensely. I was totally self destructing.
I was on medication and in therapy, which took the edge off, even though I knew you have said none of it helps whatsoever to you.
You're probably going to totally dismiss what I say, not take it into account and even go as far as saying I'm insensitive. One day I woke up and knew I didn't want to continue like this anymore. When it comes to mental illness, there's only so far that people can go to help you. You have to toughen up and help yourself. It's hell. But I knew I couldn't stay in bed day after day anymore and wallow in self pity. I forced myself and dragged myself out. I started out small. Doing a bit of work. Applying for a few small part time jobs. The sense of achievement you will get after this really will boost you.
I also tried meditation, yoga, read a lot into philosophy such as The Secret. I changed my thinking from negative and self doom to positive and optimistic. I came across people who influenced me positively.
I'm not being insensitive but what do you want? What do you expect? Do you want to be one of the small statistics where everything fails you and you just wither away and die young, tragically? If not, then do something about it. I'm not going to wrap you up in cotton wool and tell you it's such a shame you are ill, which it is, but that won't really help you. There's only so many times when you can victimise yourself, attack those who give you tough love, be over defenceless and make excuses of why you can't live. Take some responsibility. Beat this disease. I won't lie, it's the hardest thing you'll ever do. It will be exhausting, take a lot of determination and motivation, be hell but it can be done. Many people are proof of that. If you don't, you'll just die. And you'll die with a wasted life.
Don't cut this old friend out of your life. Like you said she's the only one who bothers to check in with you once in a while. She clearly cares as she's attempting to help you. Don't compare your life to hers. You are two different people who will always have two very different lives. Comparing your life to someone you think has it good will never help you. And who knows what's happening behind closed doors? People on the outside think I have an amazing life but right now, I'm going through something that's tearing me up.
How about send some CVs out, even if they don't amount to anything? Explore talents you have? If you don't think you have talents, then this is a time to discover them. Be creative. Paint, write, play an instrument. Meet up with this old friend, get out the house and refresh yourself. In the future she could introduce you to her social circle. What about studying for a degree or qualification at home? Go for a walk. Get a pet. Just do something. If you refuse to do something then how can you ever expect your life to improve? Sometimes we have to work to get life, everything doesn't always come to us freely. Go out there, prove everyone wrong and beat this soul sucking disease. Live a good life because we get one.