That's exactly how I am! And I feel horrible about it! I'll be so freaking motivated to draw, and get up at like 6 am thinking "K. Gonna draw, ALL DAY" and by 3 pm, still haven't even picked up a pen -_- But when I FINALLY get working, I obsess over it because it's so thrilling and it's like impossible to stop. I didn't eat for two days because I wanted to finish this: [link]
And although I'm super super proud of that painting... Dude, I didn't eat for two days. xD That's just my personality. Procrastinate until it's too late, then start working and don't stop until miracles happen I guess. It's really annoying haha.
But yea.. I always sit down with a sketchbook like "Gonna sketch all day, gonna make LOTS of them like all my favorite artists do in a short period of time AND they're gonna look good" and even if i start drawing at a decent time, by the end of the day, I'm still refining the first sketch or doodle x__x