For me, it got to the point where the only times I liked me was when I'd been drinking.
The problem was, when I sobered up, or should I say dried out? I hated myself more than ever. As to where the self hatred came from... does it really matter? It's there. I could say that I internalised a lot of stuff I heard over the years. That I wasn't good enough, that I was a horrible person. [Apparently I should have been able to spot somebody else had slipped a disc before it happened.]
I'm working on changing that now. Learning to like me, to stop hating me. Letting go of the past.