Sorry to post yet again, but you can also simply wear out your vocal cords by talking with the incorrect pitch, which is what I have done until recently. Reference Dr. Morton Cooper's "Change your voice and change your life."
Also, have you been to an ENT? You can also have polyps, or something else.
You're not crazy. You might have spasmic dysphonia, shared by none other than scott adams, creator of dilbert. Check out his blog, or google him and SD, to see if it sounds familiar.