What happens to Meg in the beginning of chapter 4?

At the
start of chapter 4, Meg tessers for the first time. She finds this an extremely uncomfortable
and disconcerting experience. This is compounded by the lack of warning she received from Mrs.
Which. All of a sudden, Meg finds herself gone. By moving through space and time, Meg briefly
loses all connection to the physical world. All of a sudden, she is alone; she has lost her
connection to Calvin and Charles Wallace, and she can't even feel her own body or use any of her
senses.

Slowly, Meg's physical state comes back. She can gradually feel her
limbs, hear sounds, and see again. It takes a little while longer before she is able to move or
react to anything. This worries Charles Wallace immensely as he struggles to get any reaction
from Meg's inert body. Eventually, Meg comes around and finds herself and her companions in a
strange new world.

The narrator does not describe exactly what is involved in
tessering, but it appears to involve bending space and time in order to travel great distances
in a moment. Such a method of travel, Meg finds, is very uncomfortable and
strange.