Word or expression to describe the feeling of nostalgia for a place, for which you no longer have nostalgia

I think "BITTERSWEET" suits the situation very well.

Meaning :

arousing pleasure tinged with sadness or pain
happiness tinged with sadness
having a taste that is a mixture of bitterness and sweetness

In your usage :

Friend: How do you feel about this place?
Me: Sad, or rather bittersweet.

Wistful

full of yearning or desire tinged with melancholy

feeling or showing a quiet longing especially for something in the past

It sounds like the place makes her feel wistful. Sad that the she can't feel that way again.

You can't go home again

The place has changed, and/or you have changed, so the experience will not be as you remember it.

Ambivalent.

am·​biv·​a·​lent | \ am-ˈbi-və-lənt

having or showing very different feelings (such as love and hate) about someone or something at the same time

^{Merriam Webster.}

I felt ambivalent about the saturday night curry, delicious as it would be, I knew I'd pay for it on sunday.