Well, generally speaking, stress can not change the color of your eyes. According to some researches, stress is not a factor which can change the color of the eyes completely. But on the other hand, stress can affect how dark or light the eyes become in color. You should know that when you suffer stress, the density and distribution of the melanin on the eyes will change. In this way, it will make the eyes look darker or lighter. By the way, you should know that the color of your eyes can change with the emotion. When you are sad and cry, it can turn to light grey and light blue. Even some drug which will have side effect that it can change the color of your eyes. so just be careful about it.
Yes, it is possible for you to change the eye color because of stress although we know that the color of eyes is fixed according to the genetic endowment. Once you have the stress, you will have the big change in the whole body. You will feel intense and have to focus on something you need to do. You will find that your blood circulation is done quickly because of the quick working brain. In addition, you may find that you don't have a good appetite which will affect your nutritious character in the body. Then your liver may also get affected. When you lack some elements in the body, the eyes may change the color in the following way. If you lack of Cu in the body, your eyes may change into green. If your liver has some problems, your eyes may show the yellow color. Thus, you'd better release the stress and go to the hospital to check the eyes. The change color of eyes should need your attention.
As a matter of fact, I quite understand your concern about that possibility. However, it seems that I should remind you, the color of our eyes would simply not be affect due to stress. Because they are decided by our genetic type. But too much stress could really lead to some bad consequences, such as eye strain and decreased vision. So, you need to be optimistic about everything you have, where there is a will, there is a way.