First, no need to feel ashamed, not at all. You are doing good, it takes times. Under your circumstances I do understand the 'need' for 'tapering off' rather than 'cold turkey.'
Second, I have been questioning the 'tapering' in my mind, in that I think he is dropping the dosage too quickly. Somethng I think you need to discuss with your doctor. I would think that 5 to 7 days at each level would be better than how quickly he wants you to taper down. Just might be something to consider. Allows you and your body to 'adjust' to the new dosage before dropping it again. ........................... just a thought.
Yes it will take longer to get off the codeine but might be better for you mentally and physically. I'm not a Dr and this is not medical advice, just being logical here. The slower the 'tapering off' the less stress on you.
J M H O
Love and hugs,