Can anema be brought on by stress?

Not directly: Anemia is a lack of blood in your system, and one type of anemia can be caused over time by poor iron intake. So if stress leads to a poor diet, you could eventaully become anemic. Heavy periods may also be a cause of anemia. If you are anemic, or think you are, get a blood test from your dr. And seek the treatment depending on what is causing your specific type of anemia.

Not directly: Emotional stress does not directly cause anemia. However, "stress" leading to poor food intake can lead to various anemias such as iron, folate, (folic acid) and B12 deficiency. Chronic alcohol abuse (used maladaptively to combat "stress") might do this also. Also if you have a stress-induced peptic ulcer, it can bleed and lead to chronic blood loss --> iron deficiency anemia. Just possible mechanisms.