Last one at the party
(Book)

"The human race has been wiped out by a virus called 6DM ('Six Days Maximum' -- the longest you've got before your body destroys itself). But somehow, in London, one woman is still alive. A woman who has spent her whole life compromising what she wants, hiding how she feels and desperately trying to fit in. A woman who is entirely unprepared to face a future on her own. Now, with only an abandoned golden retriever for company, she must travel through burning cities, avoiding rotting corpses and ravenous rats on a final journey to discover if she really is the last surviving person on earth. And with no one else to live for, who will she become now that she's completely alone?"--Publisher.