This book reminded me strongly of Highly Illogical Behaviour. 
 This book is about Madeline, whose entire life is books, her mum and her white bedroom with it's filtered air. Madeline has SCID. (view spoiler)[ Or so she thinks... (hide spoiler)] She can't go outside, she can only eat certain foods, there is no school, and no friends, because they can't get inside her house. 
 Then Olly comes. Olly is the new neighbour, and he doesn't understand why he can't visit her. Eventually they find a way and fall in love. 
 I really enjoyed reading this book and I couldn't put it down. I finished it in about 2 hours and re-read all my favourite parts. I loved how the romance between Olly and Maddy wasn't forced, and it just seemed natural. In some books, all the conversations are so cliche, but these ones weren't. 
 Overall, I recommenced this to anyone who has read Highly Illogical Behaviour or The Fault In Our Stars. I also really recommend it to anyone over 13 who's just looking for a good book.