Self doubts are best done prior to surgery as we all know that surgery is irreversible and once you have signed that document that you acknowledge this there is no turning back but one can turn back if there is hesitation, I can not speak about self doubt or hesitation because it was not in me but we all know all full well that like you there are many who have doubts, forge ahead and have regrets. In some ways I see post surgery to some like how a cisgender female can nose dive into a depressive state after child-birth and this can happen to us too. So the doubts and hesitation are caution signs on the road of life to heed and heed well. I so wish the very best for you and make the right decision but as I have said in the past get into a secluded place and talk about your path and were it leads along with the rest of your life in all aspects even down to what if you come away from surgery with no sexual feelings down below, losing male privileges or the mental anguish, losing a marriage or children that may come from transitioning but at the same time the reverse, the wonders of being female in all aspects once you have fully embraced your new gender and be fortunate to keep your marriage and childern.