Single Player Survival

Humanity disappeared in one night, when a guy named Alex planned to end his life to save himself from misery. not knowing whether to laugh or cry, he found himself clueless about what kind of situation he was in.

"Worry not, meeting me is your biggest luck you ever dreamed of"

As if the fate itself made a joke to him, after he know that all the people go into Isekai, while leaving only him staying in the world in the verge of collapse,
He found a mysterious woman who suddenly appeared in his Apartment giving him hope.
Now, with the system given by the mysterious woman, he needs to survive in a Single Player mode.

**Newbie Author here, please be gentle :))**