Have your optic nerve checked by an opthamologist.
Icreased estrogen can lead to a disease normally only seen in overweight woman, the disease is called psuedo-tumor cerebri. This results in a swollen optic nerve, which is usually caused by a brain tumor (but not in this case, hence the name). A swollen optic nerve can cause the symptoms you mentioned, although the blurred vision is usually only 30-90 secs.