What's the Name of That Book??? discussion

I read this book 2008-2010 but it was a book that my elderly neighbor gifted me so I don’t know how old the book is. The book itself is about a guy in highschool (I think) who says his life is boring and regular, life is grey, has nothing to look forward to, and then the book is how he wakes up and goes about his day and how through his day he realizes he is invisible. And he tries to find a way to tell his friend that he’s invisible without scaring him. And I remember scenes where the invisible guy looks in the living room to see if his parents are still looking for him, because they’re like “where is he”. And a lot of the book is set in the library and I remember reading where the guy is describing the statue at the library and says that it’s a lion. And when he enters rooms he tries to be as silent as possible because well people can still hear him he’s just invisible. And his friend and him kinda like investigate how he turned invisible and they come to the conclusion that the invisible guy consumed something and like a side effect..? made him invisible. And i’m not sure BUT i THINK he goes back to being visible at the end. Please help me find this bookkk :)

Fade?

Things Not Seen?

Displaced Person?

YESS THANK YOU IT WAS THINGS NOT SEEN. THANK YOU SMM

Awesome, glad to help out!