Sketched in photoshop.

Ok I'm really frustrated, I think I used the chalk brush in photoshop, but when I almost finished my drawing I tried to do some shading and suddenly the brush does not have that charcoal-ish, sketchy lines anymore. I wonder if I used a different brush or any mistakes I made TT__TT I'm not really a brush and photoshop pro ahhh halpp

I'll try to figure out later, so sleepy since its 4 am now =.=