Having an issue with normal maps in Unity

I've been texturing a building in substance painter, but when I export the texture maps into Unity it turns out all low-res and weird looking. Especially the normal map. It makes it look all choppy and strange.
I've exported the textures as 2048x2048 and it looks nothing like that in substance painter, so I'm not sure if its a resolution problem or not.
I've used substance painter a lot for texturing of Unity models, but this is the first time this has happened.
Anyone know what may cause this?