Silver circle ?

I woke up , turned over and saw a silver circle 4 feet from me. As soon I openened my eyes fully it disappeared. This was around 4 am and I've never seen this before. It was a dark silver just an outline forming a circle in the air 4 feet from me. My friend who Believes in Aliens said to post the question to a board . Anyone have an idea what this is? My mom said she saw a circle but it was right after her cancer surgery, near death. For me, I have no health issues