Hi, I m a 28 yr old woman, 5 6 , 120lbs.. My last two periods have been very irregular. Well I started my period last night and my lower abdomen was very bloated, way more distended than it has ever been. Also I notice a mucus like substance and blood coming out of my belly button... Also I have been having back pains in the middle of my back and my urine has been very dark yellow. What could this be?