The sign for that's-life is also used for "tough luck" and tends to
be shown by spelling the letters TL while throwing the hand forward
(sort of like throwing it in the face of the person to whom you are
signing.) The "L" ends up with the palm at about a 45 degree angle
(by that I mean that the palm is facing halfway down, halfway
forward).
You will also see this
concept (that's life) expressed by showing the sign
THAT and then the sign
LIVE/LIFE.
You can learn
American Sign Language (ASL) online at American Sign Language University ™
ASL resources by Lifeprint.com © Dr. William Vicars