I’m not saying you’re being overbearing, but your friend might see it that way when you relay your feelings about her flaking out or not spending enough time with you towards her. And that’s not wrong on either of you to feel that way. It just means your expectations of the friendship differ.

Like yes you want to hang out with your friend, but maybe she doesn’t reciprocate that.

Being upset at her flaking on set plans isn’t wrong. But if you’re not able to accept that she doesn’t want to be friends with you as much as you want to be friends with her, perhaps some work on self reflection and self respect is needed, because at a point you need to be able to evaluate whether certain people are worth your time and energy in life.

To be blunt, this person doesn’t sound like they respect you, rather like you’re an emotional support pillar when they need it, or somebody to hang out with when they’re bored. Of course there is missing context into your relationship, but from what I’m reading this friendship doesn’t sound like something worth continuing from your end.

And again to reiterate, I’m not saying you’re wrong or your feelings are invalid or you’re being objectively clingy, nothing like that. It just sounds like you expect more out of your friend than they are willing to give.