Hi,
yes I would say the same this sever depression, and you have every right to be. It sounds like you have had a very hard life. And losing your friend that had to be terrible too.
I don't blame you for being defensive when people try to help. I have alittle advice, I used to feel like you do and I used to cut myself it felt like a release of the pain I felt. I felt like no one understood me. I started writting poetry. Some days I didn't write at all, but somedays when I felt like I didn't won't to live life anymore I would start writting the way I felt. I still have this notebook I have had if for about 4 or 5 years now. Writting can help.
Have you ever talked to a doctor about how you feel? Because they could prescribe you something for depression, I have been on several different types of depression medication. And some have helped and some haven't. But I am sure if you told your doctor how you felt they would try to help you. Remember you are never alone. I used feel exactly like you are discribing yourself. I was never molested. I lost my mother at the age of 9 and she was the only person I had ever cared about, she died in a car accident after her death I just didn't care anymore or want to live. But luckily I managed to get threw it and never came out and told anyone about my cutting habit until I was 16, thats when they gave me something for depression..
But please remember there are people who care, and are willing to take the time out to help you. It won't change over night, but if you have someone to talk to I promise you will feel so much better. Because when I opened up finally I didn't feel alone for the first time since I was 9, I actually realized somebody understood.
I promise if you write me and would like to talk I will write you back.
I hope things get better for you. And remember your not alone. :)