Very hard one but one thing I've discovered is to be aware of your negative thoughts before they take root. Tell yourself even if you don't beleive it something good as soon as a negative thought emerges and repeat those good houghts every single time a negative arrives eventually you'll beleive the positive. It's a daily, hourly, second by second battle.
Pick something you really enjoy to do every day, distract when a negative thought arrives cold shower, exercise, hold a block of ice, dance, listen to music, go for a drive.
Put sticky notes if affirmations everywhere and repeat them every time you see them.
I struggle still but it's achievable

I find being selfless and thinking of others, helping others gets me out of my own head long enough to stop beating myself up. Being of service to others and helping them to acheive their goals or feel better about themselves gives back to me more than they receive. I start to feel better for being useful to someone with that comes a sense of pride and self worth. The more you give the more you get and the flow on affect is tremendous, just like a snowball rolling down a beautiful snowy mountain its amazing how even someone appreciating your assistance even just a little feels so good. Oh and of course continue with treatment, music and make sure you get out in nature even just the backyard in your pj's (preferably barefoot) ground yourself with the earth and sunlight does amazing things vitamin D is so important. Start every morning and finish everyday with at least three things you are grateful for (even if you are grateful for not having stuff) little by little you will notice changes. This is what has helped me, its taken a long time and not everyday do I manage this but I try everyday.

I try to replace the negative self talk to positive .

Get a notebook, and every day, write 3 good things about yourself. If this is uncomfotable, start with one, and hide it.
Peace and Love🤗🤗🤗🤗

Try helping others. Be compassionate towards others. I know that sounds ass-backwards, but it helped with my voices low self-esteem racing thoughts no confidence and not showing myself any love or compassion. When you help others your in turn helping yourself to understand and accept you as you. I've really enjoyed helping other's cause it's the only way to live actually when helping other people. I sponsor people in AA, so I really get into helping other alcoholic's acheive sobriety. In turn it helps me to stay sober. We've been through so much in our lives when it comes to self-love or respect, or have compassion for ourselves, we fall way short of it. So...make it, just a suggestion only, your new daily routine to help someone.

One tip I have for you, which is a bit crazy for some.
Write on a piece of paper,
"Hello Gorgeous Lady "
Stick it to you bed/bathroom Mirror and greet yourself every morning in this way.
You will start seeing your beauty inner and outer beauty and in turn start feeling good about your daily tasks completed.