Well, looking at the images, the layout looks correct, but I think you've got the diodes the wrong way around. The stripe is normally on the cathode, and the current flow is from the anode to the cathode, so the cathode end should be connected to the input of the LM2940 (which doesn't seem to be the case).
Plonking an avo between the ground connection and the input to the LM2940 will soon tell which way around you've got things. The data sheet says that the LM2940 has reverse battery protection, so with a bit of luck nothing will have been destroyed.
I really hope you didn't have anything plugged into the USB port when you tested it. The reverse battery protection may stop things going seriously wrong, but I wouldn't rely on it.
(Edit, some amendments made after checking the LM2940 data sheet).