Many people have varying handwriting. It is not strange.
If handwriting does not change at all, the person is like a computer having a fixed font. But if handwriting varies from beautiful to illegible it tells that you are a very moody person and your behaviour will change according to your mood. This makes you very intelligent but very unpredictable too. You sometimes have a very fast flow of thoughts and sometimes you are just laid back.
You are confused moreover you make others confused due to your unpredictable moods.
You can deliberately bring consistency in your handwriting which will help you to be more reliable and clear.