Yes I agree, I think its going to take quite a while after 13 years, its quite a complex med and your pdoc should be compassionate and give you something to take the edge off
Hugs
I would advise you to read through some of the old posts about withdrawal on the mental health expert forum. The previous expert there, Dr Gould, had some really good advise.
He generally recommended a three week taper but I think it takes as long as it takes. It is different for everyone.
Because you have been on it for 13 years may mean it may take a little longer.
Dr Gould would recommend taking another med, like klonopin, etc to help with the anxiety relating to the withdrawal.
Check out his responses.