This is a really good question and I can understand how this must be a very difficult situation for you. I don't want to comment on the meds other than to say well done. If they are now unnecessary then, in my experience your chances of a full recovery have just got so much better.
The AA program would generally suggest that the medication is an outside issue for you and your doctor to deal with. AA's sole concern is with alcoholism, and I think in that regard you are right on the money about step 4. Delay on the steps only seems to delay recovery, provided you feel ready to proceed. ...
" If you have decided you want what we have and are willing to go to any lengths to get it, then you are ready to take certain steps" It is up to you to decide when you are ready, and the number one rule of sponsorship is never to get between the newcomer and step 12.
My experience was that I carried a burden of misery, guilt, and shame, bad memories that kept me awake, strange behaviour that kept me in conflict with my fellows. I had a number of issues troubling me, about which I was not really aware. I was my own worst enemy, but I needed to take steps 4 and 5 to both understand that and get some relief from it. This baggage was blocking me from the sun light of the spirit.
Pre-steps 4 & 5, I had regular spells of great anxiety and fear, seemingly coming out of nowhere. Probably appeared a bit like depression. I couldn't make any real progress, and I would end up feeling so bad that drinking looked attractive. This baggage was too much for me to carry and I could see eventually I would fall.
Something is happeing with you, and it seems similar to my experience. I went from point blank refusing to do those steps, to feeling a definite need to get them done, some how realising that I would not recover any other way.
Timing is the thing in question. How much time do you have to get this done, before the obsession comes back. No one, not even your sponsor, knows the answer to that. Appendicitus is a good analogy. It is a readily diagnosable disease, with a very quick cure through surgery. If it is left untreated, eventually the appendix will burst, resulting in serious complications, possibly death. Nobody knows how long it will be before this happens. When a patient is diagnosed with this condition, you would be unlikely to see the doctor counselling delay.
If you were a member of my group, I might offer to help you with your fourth, or I might suggest you change sponsors to one who will not hold you back. I don't know your sponsor, he could be a fine fellow who has taken all the steps and has a good reason for what he is suggesting. On the otherhand, sponsors often put of fourth's when that have never done one themselves and therefore don't know how to help you.
The main thing is that it is for you to decide when you are ready, and if your sponsor won't help, you would be wise to find another way.
Parkinson's Law:" Delay is the deadliest form of denial."