Scared new rescue cat

My boyfriend & I just adopted a shelter cat, about 3 years old. The first night she hid in our bathroom. Then we didn’t see her for almost 24 hours. She had access to food & water but was hiding somewhere in our kitchen.

This is day 4. She is still hiding. She comes out at night to wander around & I can hear her messing with our blinds. She’s been eating & using the litter box when we are not around, but any time she sees us, she bolts. We’re leaving her alone & we’ve been advised to talk to ourselves around her so she gets used to our voices, but we feel horrible.

She was a shelter cat found pregnant on the side of the road, & she lost her entire litter. Safe to say she is traumatized. But any tips to get her more comfortable?? We’re definitely letting her run the show but we just want to love her & have her know she’s ok. She was the sweetest car in the shelter & so cuddly & now she won’t let us near her.