"Even if it isn't a person it's still painful."

Everything could mean something different to different people. Sebastian wondered what 'everything' Loki had lost and thought about Jack.

"I still have my parents, a home to go back to, so most people would say I haven't lost much and I should be grateful when so many others don't even those things. But Jack was my everything."

Sebastian wiped the fresh tears from his face, "I can't get him back, but is there any way of getting back what you've lost?"