It would probably be best to talk to your GP first.
Gradual withdrawal in conjunction with alternative coping strategies WILL work but you do need someone to hold your hand, or maybe just a sympathetic ear (we are here for that!)
Both my mother and sister have used and abused ADs, painkillers and sleeping tablets (for very valid reasons to start with ie a series of devastating events within a couple of years: late miscarriage, SIDS, accompanying someone dying from cancer, road accident, etc....)
I have seen them come through to the other side.
Life is just so much brighter when you are sober.
Take small steps, reduce dosage in small increments every week and add some exercise and fresh air.
Yoga, hiking, running, dancing, anything that will tire muscles and clear head.
There are some very good healthy supplements to stabilise mood. You can introduce them as you start the weaning process (Magnesium + vitamin B + omegas)
There is also a supplement called L-theanine, which I have tried myself when I was having nightime palpitations and panic attacks first thing in the morning and it does work.
Its sold under the name Suntheanine, ask in a god health shop. Its basically a fermented green tea extract, nothing more.
see [http://www.suntheanine.com/WhatIsSuntheanine.cfm here]
it is FDA approved in the US so I guess available in health shops in UK. well researched and trialed in Japan.
Now of course, you have to deal with the root of the physical pain.
I suffer from crippling sinus/allergy related pain and attacks basically start with tension headache that develops in 3 days of paralysing (litterally) pain from top of skull down neck shoulder arm.
Massage saved me. I live in Asia and have managed in the last 4 years with accupressure (too chicken for needles), foot reflexology, and tiger balm rub.
Not sure you can have access to that near you, but the principle is to accrue blood circulation to the pain area to accelerate healing process. Any heat producing camphor/eucalyptus balm will do. do try it, the smell and heat are very soothing.
chiropractic/cranyo sacral therapy also works wonders if you are in the right hands.
I know a lot of the above is mumbo jumbo to a lot of people, but it has worked for me. I think I was also just very determined not to go down the medication route because of the spiraling addictive effect.
But I think you are ripe too, so do talk to you GP and try alternative remedies. Its just basically a new hygiene of life.
Red wine works very well too!