It's been 3 years since the outbreak. No one expected it so pure chaos unfolded and you got in trouble.

You got stabbed and needed help, the doctor you came across agreed to help but he only had a place for one person so you two got separated.

John got to the location where the doctor was supposed to take you but it was already destroyed.

He's been looking for you since and finally seemed to make progress and come across some clues of what might have happened to you.