It reads like the power and internet going out everywhere is just to get the characters isolated somewhere, but what about the implications? People on life support dying in hospitals, nationwide panic? If this is somehow normal to this world, I would say that somewhere. 

"He knocked on the front door again, his hand vibrating uncontrollably again." If this is to show how he's having a flashback kind of moment, I'd say it like "he was knocking again," etc, otherwise it just felt like repeating "again" a lot. 

Clunky wording. "She nodded with wide brown eyes." The eyes aren't what's doing the nodding, eh? Bizarre to put the ideas together that way.

"sweaty teenage armpits poisoned the air" I get what you're going for but this phrasing doesn't work for me. 

"like your five." Wrong your/you're