Doors the first time you get put in a hold after getting that elusive first job as a pilot is a bloody eye opener.
Mine was in Manchester in the Rosun hold in an icle 19 seat turboprop with a heavy two engined jet above us and I had similar feelings to yourself. We didn't have TCAS in them days either so you couldn't see what the seperation was. You knew when it went over head as well because it was if someone turn the lights out.