i read that it is very possible to become pregnant ecpecially when your tubes have been clamped over the years the clamp can come undone or slide down making it possible to become pregnant so you should see your gynacologist and have them check and see what has happened it also could be minopause if you are older so see your physican and they can tell you more about what has happend if you are pregnant or you are going through the change of life.