It just means you are better at critical thinking that imagination. It isn't a disorder, just a means of how your brain processes information. You use less of your frontal lobe, which is generally where much of the imaginary or day dreaming happens. To compensate this, you will need to utilize your critical thinking abilities to come up with an alternative to visualization.
The good news is that your dreams are not affected by this condition, so you can still have very vivid dreams.