I'm sorry to hear this... but it seems like your trauma dumping and depression was effecting her well being and she had to do this.
She was at full capacity and could only handle soo much. She also has problems to be sorted out in her own life as well.
She was already down, and you were bringing her lower...possibly to a spiral.
Also, you insulted and offended her by accusing her of not being there for you, when it sounds like she was...just not in the way that you wanted.
She was there for you the best way that she could be at that time, while juggling whatever was going on in her own life.
No one wants to listen to someone overloading them with their problems. . and someone who is clingy and overbearing.
It was insensitive of you to not take her well being into consideration.
You were demanding of her time and all her energy, and it exhausted her.
Next time, don't continously trauma dump on someone. If you're feeling these ways, it would be best to talk to a professional.
Also, if she was your only friend, it may have been exhausting for her, because you relied on her a lot, and perhaps didn't allow her much personal space over the years.
This is why perhaps you should have a variety of friends and associates. You expected too much out of her.
Just leave her alone, and please don't contact her...especially with any snarky insensitive messages.
Sounds like you were the cause (intentionally or unintentionally) of the demise of things.