Exhausted by Clingy Child

A friend if mine lost her husband suddenly earlier this year. Now a single mom, navigating grief, with family living elsewhere, I offered to help with her little girl on my days off.

Her daughter (7f) is a year younger than mine, and they get along like a house on fire. 7f is a really polite, well behaved kid. In the few months I've been watching her I've only had a problem with her once when I had to talk to her about painting nail polish on stuffed animals and it hasn't happened since.

The only thing is that she's terribly clingy. She wants to be close to me, cuddled up with me, or up in all my business whenever she can. I know it's because she's missing her mom while she's at work and still navigating her grief from losing her dad, so I don't complain or scold. It makes me feel good that she's so comfortable with me, but darnit, I have things to do and by the end of the day I'm totally touched out. My own kids aren't this clingy.

How do I help this poor little thing without getting touched out or hurting her feelings? I want my house to stay a safe space for her.

Any thoughts?