Disc shaped object came down from clouds, hovered for 15 seconds, then slowly went back up into the clouds.

I had just turned 12 years old and the young 5-year old girl I baby-sat for, who lived on the second floor of my apartment building, was talking to me from her bedroom window as I was outside on a typically overcast day. While I was looking upwards at her, something caught my eye to the right but somewhat almost overhead in the clouds, and I looked over and saw a dark gray disk come straight down from the clouds and hover underneath the clouds, in total silence, hovering with just the slightest of movement (there was a bulbous shape in the center of the disc of the UFO) and as I stared at it in shock for 15 seconds or so, it slowly lifted up and back into the clouds again, where nobody could see it. I was in shock and it felt surreal. I am 49 years old now and have looked for one over since because I KNOW they exist. I hope to see another sighting in my lifetime! I was not afraid at all -- it just seemed like they were looking at us, and then they went on.
 Thank you for this website. I have always wanted to report this!
Date is approximate.  PD