Sometimes with snakes signs of stress can be very subtle or take awhile to show something obvious. One of the most common signs of stress can be refusal to feed. This can be caused, however, by a lot of other factors but it's generally held that if your snake suddenly starts refusing, overhandling can be one of the issues. Every snake is different, just handle with respect for the fact that this is a shy, nocturnal and undomesticated creature. Handling is more about what we humans want more than what our snakes need.