Do you prioritize your time?  Before you head home for the night, schedule your next work day in your calendar.  Leave time slots open that will allow you to react to the day's events in case that important customer calls and asks you for a last minute project by the end of the day.  You will have open times in which you will be able to work on the project and still stay on schedule.  Stay true to your schedule and you will find yourself achieving more during the week than ever before.