It is a common condition. The reason that one of your eyes dilated but the other not can be physiological, benign or life threatening. It can be the result of physiological anisocoria or mechanical anisocoria. Or Adie syndrome and Horner's syndrome can also manifest such symptom. In addition, if you suffer from inflammation such as iridocyclitis, diseases of the iris, paralysis of the third nerve, angle-closure glaucoma, diabetes or syphilis, one of your eyes would dilate while the other not. I advise you to go to hospital and to ask an ophthalmologist to do an overall examination for you.
Well, yes of course, your description is quite terrible and indicates that there is something wrong with your health. Our eyes would sometimes be dilated out of some reasons both at the same time. And your situation is quite weird, maybe it is due to some physical injury. Or there is something wrong with your nerves, try to take an eye exam and get vitamin pills to swallow, also try to protect your eyes in every aspect.
Well, it can be normal to have this kind of situation. So you do not need to worry about it. Generally speaking, there are many reasons which can lead to dilated eyes. For example, high blood pressure and anxiety can lead to it in some degree. So when you have high blood pressure, it can just affect your eyes, and then leading to dilated pupils. But maybe the high blood pressure only affects one eye, and that can only cause one eye dilated. Also, you should know that drug use, illness, and trauma can cause it too. Anyway, for your situation, just go and see the eye doctor as soon as possible.