I can completely relate to what you are saying.

For reasons that I can't fathom, my mom is a child. She would love nothing more than to live with me (or my sister) and have us tell her what to wear, what to do, feed her, entertain her, take her everywhere with us....She makes me feel guilty..(Oh, don't worry about anything!...I'll manage"), and she makes me feel responsible for her happiness...

Somewhere along the line, our roles reversed and I became the parent. And she liked it.

To be clear, I love my parents very very much. I know how my mind is supposed to work when it comes to them. But something certainly is dysfunctional with us...One of us is wrong...

I believe your predicament is similar to mine....We are the ones who feel that we are always in the wrong. We strive for approval that we will never get...
From what you say, you feel guilty (that's what made you post, I think..guilt).

Leave the ball in her court and tell her that you're there for her if she chooses to get in touch with you.

You did not do anything wrong.

It's all on her and she doesn't get to manipulate you any more.

It's okay to be nothing more than a friend to your parents.

(sorry for the lengthy post...)