This is a fake friend, not a real friend. And not to sound harsh and I certainly don't judge you at all, but in all honesty, I think you gave too much of yourself to this Kate person because you are a people pleaser and are likely empathic. You went to great lengths to support her during her troubled times, and she likely did use you or lean on you as her substitute therapist when she needed you. Then she doesn't respond to you, but you kept doing things for her - like reminding her of her own responsibilities with the art class, agreeing to do things when you didn't want to and when it went against your own values and doing things for her.

This problem you have with this woman sounds to me more like a boundary issue on your end, which is something to be aware of and to work on - I have had poor boundaries myself and have gotten burned that way with friendships too, so I am not judging. I am pointing out to you that if you strengthen your boundaries, say no when something is against your values and say no when you want to say no, and don't bend over backwards to please other people including new friends, you will be better off. The fact that this woman's problems plague you or that issues with this woman plague you while she barely gives you any thought tells me you are likely an empath and yes, people pleasing.

People pleasers must learn and strengthen their boundaries - I have been one myself, so I know what this is like. You have to live life by your own values and beliefs, and not compromise your values or beliefs just to please someone or to maintain a friendship.

And like I wrote earlier, this friend is/was a fake friend. She cared more about going on her dates than she did about holding up her end of the art class responsibilities or responding back to you showing common courtesy.

I cannot say whether she is a narcissist - but empaths and narcissists are naturally drawn to each other and do this kind of a dance together. The narc gets their fill because the other person makes them the center of their world, and the empath ends up being completely drained and resentful from giving too much of themselves.

It's good you decided to do your art class the way you want to do it - that's standing strong in your own values. So, good for you for finally drawing the line and doing it the way you wish to.

As far as Kate goes, I would distance myself and I would not consider her to be a true friend.