As an amputee, I will not attempt an argument by anecdote, as I must state, every amputee is different. I can tell you one thing though - phantom pain for me is a tingling and electric sensation, thought for the first month after my amputation it felt like a hammer. After that, it became just tingling. The best comparison I can make is if your leg falls asleep and it tingles as you get up and try to move around again.
As for Hood's sleeping problem, phantom pain will cause a loss of sleep. I used lay awake in the hospital bed at night rubbing my stump with a compression sock to get the ****ed tingling to stop. Opiates help to alleviate that pain and allowed him to sleep. In my case the doctors would administer Hydrocodones if they were needed. He stopped taking them when he could sleep without them. On November 24, 1863, as the good doctor noted.
As to psychological issues, I ... to be frank, it was terrifying. I was aware of that they were going to amputate before I went into surgery and I lost control of my bodily functions on the gurney. Afterward, I could not look at the residual limb for almost a week. The worst part was when I woke up from the surgery. It felt as if my foot was still there. I was happy. Maybe, I thought, the doctors had not taken my foot and it had been saved. I looked down once. Bloody swollen mass where my foot used to be. There was shock, and then I felt a hurt like I had never felt. And I couldn't look down again for almost two weeks. I came to terms with it on my own, but it wasn't easy. I wouldn't wish on my own worst enemy. And I say thank God for morphine.
The great irony is that I had bought Sam Hood's book on the myths surrounding Hood before the accident but hadn't read it yet. Being in the hospital three months gave me an opportunity to read it. It was oddly comforting, especially the chapters on Hood's own amputation and medical treatment. This whole ordeal has given me insight onto amputees like Hood and Ewell and Howard, if not a little bit of sympathy.