I am 34 years old, 5'6, 135 pounds and have three children. Recently, I have had periods of feeling nauseous, light-headed and of having no energy. I have found that during my period and a couple of days before, my energy level is up and the symptoms disappear during this time period. I was diagnosed last year with endometriosis and am on Mirena to help with the symptoms. Because of this, I don't often get my period and it is difficult to predict when I am getting it (or even having it because it so light). Is this related to that diagnosis or are these symptoms somthing else?