There should be structure to your day. If you can't plan what you are going to do or force yourself to wake up then it's crazy.
it does not matter when you wake up (5a,, 10am even 3pm), just make sure you have 16-18 hours per day alottted for what you want to do and achieve.
I have a whiteboard with monthly, weekly and daily goals. I focus on what my aim is for the month, split it into 4 parts, 1 week per part and then at the end of each day I work out what I will be doing on the next day.
I have an old alarm clock and wake up at 6am each day. I give myself an hour to wash and eat, then I go to the office.
Work until 12, take an hour to walk/eat/do day to day stuff.
Work until 7/8pm when I have finished my daily tasks, work out what to do the next day and the rest of the evening is mine.
If you are working for yourself and complaining about a lack of structure then you need to build one!!!!!!!