Cutting off a friend or not?

Hi everyone!

This is something i've been thinking of for a while. She's a really good person, but has some mental health issues(mostly anxiety and depression but she's a huge hypochondriac) that aren't diagnosed and she makes a very big deal out of them on a regular basis. (I'm not saying they aren't, it's just in her case)
I know if i'd need her she'd be there for me, but I don't feel the need to open up to her.

She's a genuinely good person, but she exhausts me to the point where it becomes physical; she's loud, needy(touchy, i feel guilty when telling her i'm not comfortable with something as simple as holding hands, clingy; needs constant validation, frequent hanging out...) always in some drama, complaining and asking for advice.

And even though I know I could freely return everything listed and not be judged, invalidated or not accepted, I don't need/want to.
She is too much for me, and I feel guilty for even thinking to cut the ties with her. Even if I left her in my 'outer circle', I can't distance someone off because of their (possible) mental illness.

At the same time, I can't set boundaries or tell her how I feel- that's just how she is. She's loud and eccentric, a good friend but really emotionaly and energetically demanding. I think she considers me as a only real friend.

I'm kinda lost, sorry for the rant
thanks for staying!