Thyme Dying Following Harvesting

I have a container herb garden. I have purchased 3 different types of thyme to place in my garden. Each time, I transplant it and it thrives. Then I harvest some and within 2 days the whole plant is dead. This has happened to me 3 times now. What am I doing wrong?

You might be cutting off too much of the plant so that the roots don't get enough food anymore and starve to death- result: the rest of the top dies too. Always leave at least 6 inches (15 centimeters) of the base of any portion of the plant you want to survive.
Also, when you do the harvesting make sure that the implement you use is sharp and that the roots don't get disturbed with pulling on the plant. Pulling would rip off all the fine root hairs and would then require that the plant would have to regrow all the active part of the root system. This can be too much of a shock and kill the plant.
There is great variation in the firmness of rooting and stored energy of plants and very few plants keep coming back after root injury and mutilation like a dandelion! If they did hoeing to control weeds would not work at all.