I can relate to a lot of this, I too have been isolating myself and loosing friends. I also like to write. For years I used to feel the same way but recently I have decided I don't care, no one will probably ever read it but I enjoy it so I will keep going. I have gone over and re-written my novella twice, and it became better each time. You should keep doing what you like.
Don't be to hard on yourself, I tell myself at the end of the day no one is judging me as harshly as I judge myself. I have a new motto which is "Life is short." I have tried so hard for too many years to do my best to make others happy,I have decided to just let it go and try to enjoy the small things.
I too have been suicidal, if these feelings persist you should be seen in the ER. I have found antidepressants have greatly helped me in my journey, I am slowly finding reasons to live again and you will too. Please keep us posted, I hope you are feeling a little better. It's ok to rant, that is what we are here for