HI. I'm 26 and I had my tubes tied 4 years ago. My menstrual cycle has been pretty regular until recently. I had a period about two weeks ago. The next week, I was extra tired, emotional and nauseated. Now I'm having another period, this time it's much more heavy and painful and my body just feels weak. They are less than a week apart from each other. I've had this happen once before. What could be causing this?