You said you used a color grid to determine the top and bottom, which is great, you didn't say if/how it was labeled tho. Here's an updated version of the color grid I used when I started UV'ing. Its a color grid with text added so you can better tell where on the grid you and, and more importantly what the orientation is. Eventually, as I got more experienced I moved away from the labels, to just a plain grid, but they help when you're starting out.

Keep in mind, that's its okay for things on your UV layout to be oriented side-wards, and upside-down, etc, that's normal. You'll get used to rotating stuff in GIMP to match the orientation, or rotating the whole canvas while you're working on one section if its orientation isn't "vertical". When unwrapping you want to prioritize having as few seams as possible, and placing those seams in inconspicuous places whenever possible, and that will come at that cost of sometimes having sections upside down on your UV layout.

Sorry, if this comes off as patronizing, I don't mean it that way, I don't know what you're experience level with this sort of stuff is.

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

Lightwave | Blender | Marmoset | GIMP | Krita