OP, have a hug.
Sometimes, your life tells you it's time to make changes.
Get yourself on a waiting list for talking therapies. Read the book 'Mind Over Mood' in the meantime.
If you love your daughters and your mum, tell them. By text, if necessary. Don't expect anything back, don't engage if they want to re-ignite some kind of fight. Just leave the love there for when they want it.
Any one of the examples you gave would bring a person low, so don't blame yourself at all. Be kind to you. We can only start from where we are - we'd all be better people if we could, but we have to start where we are now.
Mindfulness.
'This moment, now.' Bank every happy (count 'barely acceptable' in your present circumstances) moment. Have a shower or a bath - the good feeling from that counts as a positive moment to bank. Bit by bit, you'll learn to recognise happiness and joy again. It's smaller, less demanding than you think, but you can't force it. At the moment, hanging on is enough.
Crying isn't a bad thing, and the feeling of cold water on your face afterwards is quite pleasant. Bank it!
Can you find solace in music? This is working for me. .
Hang on. You're worth it. No matter what has gone before, the future can be better. Good luck. x.