Agree with JC: Post a recipe. Meanwhile, oats are known for giving beer a "creamy" mouthfeel. If the beer is done, either lactose, as JC suggests, or maltodextrine. the advantage to maltodextrine is it's flavorless, while lactose is slightly sweet.
Just brewed an Oatmeal Milk Stout and used both oats and lactose. Took quality control sample during gravity check after 5 days... very creamy with a slight sweetness. But that could be that the gravity is at 1.020. Once it gets to 1.016 it might lose the little seeetness.