"Uh why do I feel sheepish?"

I went to get the rest of my books for school today. I'd already gotten 3 of them, 2 used (8 damn expensive books and only two used, and one was one of the cheaper ones anyway), and I got more money to go buy the rest. First thing I go to find, the multivariable calculus solution book, not there. Anyway, I go to get the other 4, but only get three. A few days ago I checked and found they had it for nearly 10 bucks cheaper at Borders, so I decided to drive over and get it there (I stupidly ignored the price match posters they had in various places in the college Barnes and Nobles for reasons beyond my grasp). A 15 minute drive later, I arrive and get the book (I think they marked it up like 2 or 3 dollars since I checked, but I can't be sure) and realize I don't have enough cash left over to buy this $80 book. Then I think, no problem, I'll just use the cash I have, and pay the rest with my debit card. I feel stupid enough at this point, but the real topper was when I realized I hadn't brought my debit card as it has a separate little thing I carry it in, as it is also my student id. So now, I've wasted a good 40 minutes of my time for absolutely no reason at all, I feel stupid, and I'm hot from all this rushing around in a truck with no a/c. Fun!