Its not necessarily upside down, but half your textures certainly ARE upside down and that's the way its supposed to be. Your unwrap looks fine.

Can I recommend googling a "paper cube template" to cut out and assemble? Look for one that resembles the way the seams are on your UV layout. You don't actually have to glue the cube together, but print a couple out, draw on them a bit, and at least fold them into the cube shape. I realize it'll probably seem like a grade school task, but I think it might help you better understand how 3D space translates to 2D UV layout space.

Here's a quick example of what's [likely] going on with the UV layout you used. The "Right" and "Left" sides, are always going to be opposite of each other, so if the right side is "right side up" as you look at it on your UV layout, then the left side has to be "upside down". In this example, the "front" and the "back" will oppose each other as well, tho they'll be 90 degrees off the vertical. [Note if you unwrapped with the "right" [or left] as the unifying side, then the "front" and "back" would be oriented vertically.]

Note - You didn't indicate which was the "top" in your UV layout, so this assumes that you put the majority of seams on the "bottom" surface [which is what I would do for a loaf of bread], so that everything connects to the top. If you did it differently, that's OK, you'll just to think of the orientations a bit differently, and that's where the paper cubes will help.

Core i7 950@3.02GHz | 12GB Corsair Dominator Ram@1600mHz | 2GB Geforce GTX 660

Lightwave | Blender | Marmoset | GIMP | Krita