Don't scare yourself. Withdrawal for you will be mild if you follow avisg's advice above. You can keep reading these posts and asking questions as you go along. There is nothing to fear, it is not like in the movies. WD is like a case of the flu. The 3rd and 4th days are the worst for most people, and every day after that you will start to feel better and better.
Stay connected to this community. They are wonderful people, much expertise, and will give you support.
20 mg a day I would just taper off go down to 15 mg then 10mg then 5 mg then your done you are on a very small amout so WD should be very mild .I think tapering would really work well for U