How to change the day back at night ?Do I have " brothers " ?

About a year ago I began to work on itself. I do not have " a clear timetable. "When I want to work and then. Accordingly, and I spend the day the way I want to.Recently I changed day and night. I wake up at night, go to bed at noon. How to return everything back ?Is there anyone among you " owl ", as I am?