If your text has not been professionally copyedited, it probably needs copyediting rather than proofreading. Ideally, copyediting should be done early on in the production of a book or document, while proofreading should be a final check, involving only minor corrections. Good copyediting at an early stage can save much unnecessary work and cost at the proof stage, when corrections tend to be much more expensive, especially in print publications. In online publications and web pages, the distinction between copyediting and proofreading is, naturally, more fluid.