Put some time and distance between her and you. Leave it to her to seek you out. She is taking you for granted. She pulls what she gets away with. That's a habit and you can, possibly, help her break it. But you have to give her consequences for being out of line. As your close associate (I'm avoiding the word, friend.) she knows your tendency to doubt yourself and makes the most of it to vent her negativity.

Maybe you are a horrible person. In that case, why does she bother spending time with you. Next time she starts this stuff, tell her that. Say, "You know, I really am a bad person and you should not have to put up with me. Go find someone more worthy of your time and attention." Then leave her presence. She'll come to realise that, either she stops this miserable negativity, or she you will not be around her.

We all have faults, and I'm sure you have yours. But a friend can approach you, if there is an issue, in a constructive way. Other people don't really "make us feel" this way, or that way. If we have insecurities gnawing away at us, someone who knows us well can aggravate those insecurities. This is usually because, somehow, that makes them feel superior.

You have to make up your own mind whether you are dirt, or not. If you kind of think that you probably are not worth much, then you might as well not be.

People who are "dealing with issues" don't, just for that reason, become total $hitheads to other people. A person might become a bit irritable and act out of sorts. When a decent person does that, they say, "Forgive me, I'm out of sorts today." There is an old saying: 'You teach people how to treat you." I believe it.