The Orphan Army (The Nightsiders series)

Milo Silk and his mother belong to a small, makeshift group of survivors in a dystopian world devastated by environmental disasters and alien invaders called Bugs. Milo records dreams in a journal because they repeatedly seem to become real, including his father’s disappearance three years earlier. A figure known as the Witch of the World tells him that he is destined to save everyone. Milo fears an attack on his camp.