Put oats, milk and water altogether in pot over medium heat. Bring to a small boil, and continue to stir until desired thickness, about 5 minutes after it starts boiling.
In a small separate sauce pan add blueberries and vanilla extract on medium heat.
Cook blueberries until good amount of juices are at the bottom of the pan. About 4 minutes
Add to the cooked oat mixture.
Stir until desired consistency is reached. If you like a thicker oatmeal, add less water.