I was only gone a minute.

It's summer time and you're swimming with your friends in the lake near your house.

You dive off your floating dock, but when you come up for air you feel the chill of winter, snow is covering the ground, and all of your friends are floating dead next to you.

{This could be Space by suiting up and making a hull repair outside. When you return, the gravity is off and everyone is floating dead. You see a memorial marker in the main common area showing you were 'Lost' six months ago while on an EVA.}