Do you live in an area that has them in high numbers?

They might be reclusive nesters, but they're a hunting spider and they constantly roam around looking for food. They'll roam around your bathrooms, blankets, clothes, and they're fast AF boii.

Important things are keeping your bed away from the walls, checking the blanket and pillow before you get in bed, and checking clothes and shoes before you put them on, since like you said, they can bite if trapped between something and your skin.