I would go. She was sick on Friday with a cold. Yeah colds suck but a full week after she shouldn't feel like death- she should almost be completely better. If she chooses not to go, that's her decision. If she resents you for still going, she has other issues going on IMO. You've had this trip planned for a long time and to cancel because all the sudden she doesn't feel like going, that's not right.
But honestly, she may have just had a rough day with the cold and will change her mind when she's better. Please keep us posted!