How do I know if I have glaucoma? My eye is red, and I have been seeing strange halos when I look at lights. Sometimes one of my eyes hurts a lot. Could this mean that I have glaucoma?

Get examined. You need to have an eye examination by an ophthalmologist. There are many different conditions that may be causing your symptoms.
Need an eye exam. You need a thorough eye exam as soon as possible. This could be many things, such as a surface problem as simple as dry eye, but could also indicate elevated eye pressure, which is a risk factor for glaucoma. If you wear contact lenses, stop wearing them immediately. Most importantly see an ophthalmologist asap.
Your . Your symptoms could mean that you have glaucoma. Narrow angle glaucoma can cause the kind of symptoms you describe. You should have an eye examination as soon as possible to determine what your diagnosis is.