Relax, it may not have been from your actions. Tempered glass will get stressed if theres a tiny chip or scratch on it, even unseen flaws can create a stress point. If that was the case, it just waited until you tried to install it to break. Even sitting in the sun could have made it explode into diamonds.
I did auto glass for years... the stories i could tell, lol.
all auto glass is saftey glass, winshields and some flat side glass is laminated, curved window glass (except windshields) is tempered.