This is always the problem when you take such type of medicines for many months and then withdraw them fast.
One can always adjust to the withdrawl symtoms,if he acts judiciously.
You should have withdrawn this drug by reducing 5 mg every month.
This way your body would have adjusted on slightly lower dosage quite easily and without putting your system at stress
No doubt,it would have taken many months to come out of the drug,but you would have been comfortably out of the drug with minimum of withdrawl symptoms.
You can still do it this way.