why do i have a black and white mesh on solid view mode? I didn't use the program for like a week or so when opened it, it was like this 

and didn't know what had happened, when started to look around my files they were all like that 


checked all the textures (they were fine), check rendered mode (it was exactly as I left it). I have no idea what could be the problem and from certain angles, I'm having way too dark shading.
please help


EDIT: it has no light in the scene and the metacaps are off, I checked
Maybe you are using the black and white matcap you can uncheck or change it on the right panel (press n to get access to the panel)