OP I don't know what's happened, but I'm telling you now, everything you are thinking right now, they are just thoughts.
What you think and feel about yourself are just thoughts. They are not real, they are not reality and they can't harm you.
If someone else has told you something negative, again, they are simply giving an opinion. Their opinion is not fact. If someone says you are a horrible person, it doesn't mean you are, it is simply their opinion. What is the actual evidence for it being true?
The only opinion that truly matters about yourself is yours. And you can change it. You don't have to think any of this. They are just unhelpful thoughts, causing you misery.
You need way more self confidence and self esteem. How do you do that? Speak to yourself as you would speak to your child, or a close friend. Would you tell your child or your friend the same things you tell yourself? No you wouldn't. You'd support them, reassure them.
Any little positive through the day, praise yourself for it. Process it. Tell yourself well done. Even just the little things, like getting out of bed, if you like. Went to work? Well done, you're getting out there and providing for your family. You're dedicated.
Got out of bed and made breakfast? Well done, you're giving yourself what your body needs, you deserve it.
I've had a lot of therapy and this helped me massively.
Here if you want to talk.