I would say its probably a standard withdrawal symptom that will go away but yes you definitely should speak to your psychiatrist.
Hi
The only one reason i can think of right now, is that abilify may cause you to have high blood sugar (hyperglycemia). This is why they tell you to talk to your doctor if you develop any sign of this such as increased thirst or urination, excessive hunger, or weakness. More crucial if you are already diabetic you should regularly check your blood sugar levels. In fact most AP's do the same, seroquel another example
So my view is that perhaps since you stopped it, you get what is called a reverse action like hypoglycemia in which case you get headaches of course. but i would suggest you become a little patient as these headaches will automatically subside since your body returns eventually to its original status.
don't worry and don't take it on your nerves. forget it for a while and take some aspirin for a few days.