Do i have glaucoma(eyes)? pls read the detail below to find out my symptoms and conditions pls help me out.?

whenever i get exhausted or under hot sun and sometimes even when i am not exhausted and FEELING good,i am able to see only wats straight to me and if i keep my eyes straight and try to see wats on my sides its black.that is my vision gets confined to a smaller area.sometimes accompanied by severe eye pain.my ophthalmologist says that i've bigger optic nerve than as normal.i've also done Field vision test but there was no significant results.please help me.