I'm Seeing A Square Image That Appears Randomly Moving Left

I'm seeing a square image that appears randomly moving left to right in a descending fashion. I've had a discharge from my right I and thought it was because of this discharge. I tried covering one eye at a time and it still appeared. I finally took my glasses off and still saw the image and finally closed my eyes and still say the image. This has happened in the last couple of days. I also have had a mild headache today.