I'm The Asshole Who Borrowed My Friend's Textbooks Without Asking...

So yeah, this happened recently. I was supposed to meet my buddy Jack for coffee and study session before finals week, but he canceled on me at the last minute because his grandma was sick... which I totally get, by the way, family stuff always trumps everything else. But uh, I had already planned out our whole day of cramming in the library. We were supposed to go over all these important topics and even review each other's notes from class. Well, Jack had this one really good textbook that covered everything we needed, so he lent it to me... except he never did because he bailed last minute. Now there's no way I could get through the rest of my studying without his book. So what did I do? I just walked into his dorm room while he was at work (totally within my rights as a roommate, right?) and grabbed it... with zero warning or permission from him. The thing is, I thought I’d be doing us both a favor by getting ahead on our studying schedule, but I also kind of knew in the back of my mind that this wasn’t exactly okay to do without his consent. Now Jack has no idea where his book went and will probably freak out when he finds it missing... which could potentially ruin our friendship over such a dumb thing. Am I really being an asshole for taking his stuff? Or should he have been more prepared by keeping the book locked away if he didn’t trust me with it? Leave your thoughts in the comments because I need to know if this makes me super evil or just kinda selfish...