Okay, well since this is the second time I've run across this in two days, I'll speak the other side.
Littlewriter, this is probably bad. They all say so. But I will tell you this, someone said something to me that changed everything. "I can't be bothered to write the same book four times." There are some of us who work this way, the way you do. You didn't say how long it takes you. Obviously, if you can't get out of chapter one, then there's a problem.
The way I work is a chapter at a time. Sometimes a paragraph at a time. I write it until it's right. There is no second, third, fourth draft looming over me. I'd end up despising the thing. I'll take a pass at the end of the entirety, but I don't expect more than minor tweaks.
It soothes me to have a finished work behind me. I don't keep looking over my shoulder knowing a sad pile of less-than-my-best is watching me type off into the distance.
I'm not knocking the usual prescribed method. Obviously, it's the usual prescribed method for a reason. But if your work is moving along at an acceptable pace (for the amount of time and effort you allot it - therein lies my problem. I'm distractable.) then you may not have a problem at all. If it bothers you, try the other way, see how you like it and what makes your words flow.
Good luck!