I have a secreting pituitary microadenoma. i have severe headaches, blurry vision, nausea and depression. doctors say this can't be causing my symptoms?

Which doctors?: Depression is a very complex condition, and may be a final common pathway from many starting points. Even people with pituitary microadenomas may have additional life areas or behaviors contributing to depression. It sounds like you may also benefit from a psychiatrist being included in your medical team, to help bridge the gap between "mental/emotional" and "physical" here. All works together.