The fact that this has been going on for years, and that you feel the procrastination is holding you back from your full potential does sound like it could be ADHD, as others have mentioned. Also, ADHD tends to run in families. So if your dad is the same way...
Most people associate ADHD with kids who struggle in school. But highly intelligent people can have it too. It still holds them back from reaching their potential, it's just that their potential is much greater.
Here are some things to ask yourself:
* Do you also procrastinate non-work things such as buying gifts, paying bills, calling people back?
* What is your home like: Do you have a lot of half-finished projects, "piles", or chores that never get finished?
* Are you always running late because you are busy doing other things, or underestimate what you need to do to get out the door and get to your destination?
* Do people tell you that you frequently interrupt others when they are talking?
* Would you describe yourself as a risk taker and more prone to high adrenaline activities? How the friends you keep?
* Are you only able to focus with the help of caffeine, guarana (eg, Vitamin Water Energy), or other energy drinks?
* Do you use nicotine to relax or be more focused? (If so, please stop and see a doctor.)
* Do you use alcohol, not to get drunk or for the drink itself, but as a way to unwind or slow down at the end of the day?
This is a good book: http://www.amazon.com/Driven-Distraction-Revised-Recognizing..., which reminds me of another question:
* Do you buy/start a lot of books, but rarely seem to finish them?
Read enough of the book to see if this resonates with you. If it does, the next step would be to talk to (a) your doctor if you have one, or (b) find a psychiatrist in your area who specializes in ADHD. The book can help you find resources.
Edit: Just to be clear, this list is NOT meant to be diagnostic. Although I happen to have an MD, I am NOT a practicing physician no one should assume they have ADHD based on any list like this. I would only say that if many of these things hold overwhelmingly true for the OP, then it might be worth learning more about ADHD and finding a professional to begin a conversation.
Yes, ADHD and meds sparks a lot of cynicism in some people. However, one reason I recommended that book is that the authors present a balanced approach to meds. One of the authors has ADHD, but doesn't find that meds make much of a difference for him (they reportedly are ineffective for 25% of adults with ADHD). But they have helped many of his patients and his own son.