The breast milk means something is going on with your prolactin levels, the blurred
vision and headaches are side effects of a tumor. When a tumor presses on the pituitary, one, two, maybe even all 6 glands that are controlled by the pituitary gland can be affected.
There are 6 glands that are controlled by the anterior pituitary, they are
ACTH, TSH, HGH, FSH, LH and prolactin.
Did your doctor check all these levels?