Its my understanding that yes you can have severe withdrawl from valium,,, and your dosing seems real high on that I agree. I would call the doctor, explain about your headach and how its becoming worse,,, and ask if you should taper rather than just stop. Im thinking he will say yes,, but he will also be able to give you dosing instructions on how to properly do that... so its important you talk to him first.
*Blessings of peace to you*
most likely you will suffer withdrawl from valium and it can be very hard. you should definitely try to taper slowly and i mean SLOWLY. the proper tapering over several weeks or months should reduce the awful symptoms. there was a recent documentary i heard about this. it can be difficult but certainly managable. feel better soon.