OP, I 100% feel you and understand you. I hated myself my entire life...that's multiple decades of hatred. People that want you to practice self love don't always realize the difficulty in this. One simply cannot move from lifelong self hatred to self love. It's much too far and dramatic of a leap.
I had a somewhat traumatic thing happen to me that felt like something snapped in my brain. But it gave me a sort of realization. I am a human being.
You know what that is? It's a factual statement. It's not trying to overcompensate by showering myself with love. It's simply a completely 100% and totally true fact.
But look deeper into it. What does it imply? What is your view of any one human being? Humans are messy. Humans feel such a wide range of emotions...joy, despair, ecstasy, depression, anger, hatred, fear, curiosity, apathy, anxiety, jealousy, etc. Humans are not robots. People would always ask me why I was so hard on myself and I always thought "well it's because I know better than to [fill in the blank with whatever you want]". But that's not how living creatures work. That's how it works if you're a robot. You input a code and a result is outputted. That's not how it works for a living, breathing creature.
We like to think that we are so far superior to the creatures like squirrels and birds outside our windows. But we in reality are not so different. We are these wondrous and confusing creatures made of flesh and electricity. We don't always make sense. And the important bit in all of this is that any living being deserves a chance for compassion and empathy and understanding.
I started to make it my mantra. I would say it to myself often. "You are a human being." I started journaling about things when I would get upset. I would write about why I was upset. And in the end I would write something like that to myself. "It's ok that you feel X. Because you are a human being." And then I would come up with a positive thing to do next in my journal entry (like treating myself to a cup of coffee, or deciding to do a puzzle, or deciding to go have a friendly chat with someone, or deciding to watch a movie, etc.).
I didn't always journal about it. I would think about it or say it to myself periodically. Always remember. It's a factual statement. You cannot argue with it, even if sometimes you feel "not human".
I have absolutely never been one to journal. But doing this over and over again really got that to stick and I don't feel the need to say it to myself much anymore.
Another thing I have been doing ever since is that I started wearing these cheesy motivational wristbands. I have worn them nearly every single day since last fall. The words are written on the inside so the message is only for me. The one I wear the most says "fighter" on it. I feel like these things in combination really helped me a lot.
You got this, OP. Sorry for the length lol.