You might have something which a lot of people have including me, that is a desparity of the eyes, meaning you don't see center equally with both eyes.

There is a test for that ,but I can't find the chart right now, it show me with a powerful left eye and an off center right eye, so I always hit slighty left whether with a rife or Bow.

Once you know you can then adjust your sighting by moving the bow arm to whichever side you need to compensate for.