Ha ha, don't feel like an idiot! I did the SAME exact thing, which is why I asked you that first and foremost. Glad you were able to figure that out, mostly so you didn't have to go drop cash on a new cable that you didn't need!
And I use
WiFi File Transfer Pro. You have to pay to have no restriction on the sizes of files you upload, but I believe it is only $.99. There are free alternatives, but the one I used before had issues with force closing when stopping the service and the icon would stay in the notification bar until uninstall or reboot. Maybe you will have better luck with the other options though! The one I suggested also has a very nice UI!