Well, according to what you said, I can see that maybe you have overused eyeshadow, or perhaps you just let some of it get into your eyes which gave rise to some bitter feeling. Since our eyes are sensitive to chemical stuff you know? You should know that there are more than 10 kinds of toxins included in the eyeshadow . So you should be more careful when applying them to your eyes.
You may get allergies or infection from wearing eyeshadow, thus to cause eye watering. Or you may have very sensitive eyes and need to use mineral base products for your eyes. So, i suggest you wash your makeup and eyes right now. If you still watery eyes or your eyes appear red, you'd better see a doctor immediately.
The makeup of eye shadow contains the irritating chemical materials that stimulate your skin. If your skin belongs to the sensitive one, it is easy to get watering. Thus, if your skin is sensitive, you'd better choose the brand of eye shadow of anti-sensitive character or not use it. Or else, your eyes will not feel comfortable.