I'm relatively young and often fighting myself to get things done as well. I've taken steps to force myself away from distracting things and focus on stuff that needs to get done. For example, I've installed a website blocking extension on Firefox and blocked sites I'm drawn towards from 8am to 5pm, also uninstalled all other browsers (I have broken and installed chrome just to procrastinate, since uninstalled).
Right now I have a 1500 word paper to start but am stalling and finding a slow cooker recipe for dinner.
Nearly every day I am fighting myself to be productive, it can be pretty painful in its own way. I figure if I'm ultimately winning(being productive) then I am making some sort of progress in my personal growth.
What you said there is the main reason I know I have to push myself. I know if I don't then I'll just end up being disappointed in myself.
So, essentially, fear is what drives me.