Interruptions are often the author’s worst enemy. The real question, however, is how many do you invite or cause through poor planning? The next time you’re distracted from your writing schedule, figure out how you allowed it to happen, either by checking your email or phone too often or some other disturbance.
You have more control over these things than you may realize. It’s a matter of setting priorities and then sticking to them. Most emails aren’t emergencies that require immediate attention, the same with phone calls.