Why am i so silly?

When i was packing my back and preparing to go to school this morning, i realised that i had two very similar looking books. But thinking to myself, I can't be that dumb to have bought two of the same books without realising, so i happily took the book out and placed it on the table. And as you can guess, they are freaking the same! Gosh how dumb can i get man. I really have no impression at all on getting the same book. I kept thinking of the times i went to the bookshop but i really cannot remember when i bought another copy. My memory is really starting to fail me and i now i have to try to sell that away cause is redundant having two same books and its such a total waste of money, but who can i blame? MYSELF. Wonder was i daydreaming when i took the book to the counter, now i can only hope that someone buys it from me, bleah.