This is me. I have utterly despised myself since childhood. I have chronic low self esteem and low self confidence and my inner voice is a bloody bully to me.
It wasn't only recently that I realised that the voice in my head, the incessant negative bully was the voice of my family- my siblings and my parents who put me down, who chastised me for every. Single. Thing.
As a child it became me, the voice in my head was that of those around me. They stayed with me all my life- nagging, belittling, shouting at me. That's how I speak to myself. It took me a looong time to realise where my negativity came from.
I have also done CBT via NHS which I didn't find useful. However, it did teach me to become more self aware of my thoughts. And after a few years of self help on and off I have been able to slowly unpick the roots of my self loathe.
I am still at the beginning of my journey.
Going back to your op- I too feel like a horrible person despite being quite nice an never intentionally being nasty to people. However as a hold I actually remember a time when my dB said that noone likes me. I didn't say anything and left the room and cried into my pillow so noone would hear me. They didn't and I carried on with my day never mentioning to anyone ever till recently. It's this type of shit that has really messed me up with how under myself.
Is also have social anxiety as I was always told off for speaking/ asking questions and being inquisitive. I learnt very early on to blend in and not speak. Which is ok as a child but not in the real world as an adult.
It's resulted in me also not being able to drive as I am too scared. I hate going to interviews so have never had good jobs as I always fail at even basic interviews. I have only had low paid jobs despite wanting to do something more challenging.
I am going down the self help route as I can't afford to go private. I've got a small plan of action that I've decided to help me get started on trying from undo years of shit.