Set up an appointment with your doctor so you can talk about ADD (attention deficit disorder). From the symptoms you talked about that is what it sounds like to me. My oldest daughter has the same problem, she is not able to stay focused on tasks for any length of time. Her doctor prescribed her Ritalin (methylphenidate) and FOCALIN XR (dexmethylphenidate hydrochloride).
She has been taking them for years now, and it has helped her allot. We still have to remind her to take them every now and then, but her ability to stay focused has improved almost 100%.
I am not a doctor and this is only my advice and recommendation.