Wish Us Luck by Jennifer Wedmore

Catherine Perce didn’t expect tucking her son into bed that night would be the last normal thing she did for a long time. Flashing lights outside her window were the first indication, the second was the knock at the door.
Quarantined.
When a soldier, Captain Jake Deakon takes refuge in her house her ordinary life takes another twist. Together they must survive and protect her son Mitch.
Now that time is up, they must see what awaits them outside their door. Neither could expect the truth they find. Will their new reality be one they can live with?