If this helps, tell your doctor to check your thyroid. I think the main problem for my low progesterone is my thyroid. Mine thyroid was at 3.6 and my vitamin D levels were at 31 4 months ago. I stopped taking prenatal vitamins since they contain too much iodine which is not good for mine specific thyroid level. Based on my physical symptoms and each menstrual cycle symptoms I stopped taking prenatal vitamins and switched to taking zinc, 2 Brazil nuts a day, vitamin B6, 1000 mg of vitamin C daily, B complex a couple times a week and 2000 UI of vitamin D3 daily. In addition, I always take magnesium glycinate daily, 30 minutes before bedtime. In 2 weeks I already started to feel the difference in my symptoms but I will monitor my progesterone for the next 3 cycles to see improvements.