You're done. Take a much-deserved nap!
In a recent study of how college students evaluate and use information in the digital age, almost half of the students surveyed reported that they find it difficult to decided whether they have done a "good job" or not (46%), while over a third of respondents find it difficult to decide when they are finished with the research process (37%) (Head & Eisenberg, 2010, p.26).
Remember the points you learned when you were "Getting Started," namely that the emphasis now is on the process of learning how to do research. Your goal now is not to be the world's leading expert in "X." For now, you know when you are done when you have: