I have been depressed in the past and it took me 10 years of spiraling downward till i hit rock bottom somehow I bounced back up and started practicing better personal care(self love) by excercising more and going out and engaging in conversation with strangers (without putting any expectations of somthing more on them or myself). Eventually self care became easier and I stopped looking for the "why i am" of it all and focused i on the "how i can". Im not perfect and depression is still there in the background but I don't have to give those feelings all my time.
I hope it doesn't take you 10 years. It could take longer. Life isn't easy. It's even harder when you don't love yourself, and loving yourself is hard to learn from parents who don't love themselves. Break the cycle your progenitors are trapped in. Save yourself.
Have you read any cognitive behaviour therapy workbooks? It can give you perspective and some mental tools to help you kick yourself out of the self doubt and self loathing that years of abuse have engrained into you. Love yourself my german brother love yourself as a giant fuck you to those who say you are worthless.
Whinnie the pooh whinnie the pooh...