Procrastination/Distraction Problem...?

So the way I procrastinate is different than others. Most people wait until the last minute to start a project or an assignment. I watched a video on procrastination, and it said that once you start something, you're most likely to keep working on it. But that doesn't happen for me. Like I'll start doing my math homework, then I remember I have to feed my dog. So I go downstairs to feed my dog, and I see the TV is on. Next thing I know, I've been watching TV for 4 hours. So then I go back to my work, and I then start singing. So then I get up and act like I'm performing in front of an audience. You could put me in a room with nothing in it except my assignment, and I'd still get distracted. Once I start something, I can't finish it until it is four in the morning. I really need help with this because I'm not getting enough sleep, and it's becoming a problem. HELP! I'm actually supposed to be doing homework right now, btw...