I think it is hard to underestimate how much damage shift work can do to you over the years. I am a nurse and have been doing shifts for thirty odd years now. You take it in your stride when you are younger. I would think nothing of doing 14 straight night shifts or staying up all the next day after I used to finish my nights. Nowadays two or three is about my limit and I pretty much right off the day after I finish.
I just insidiously found that I got less and less sleep on nights as I got older. This coincided with other things going on in life, like the arrival of kids, which all subtract from the ability to sleep, night or day. When you start having sleep problems it transfers from day to night and you soon find you are not sleeping well at any time. The thing is you do get by. I would regularly go into work having had a couple of hours sleep followed by a couple of hours tossing and turning in bed. I used to say it was time spent horizontal that counted not necessarily the quality of the sleep but I have changed my opinion on that now that I am sleeping a bit better now. I certainly can tell the difference.
I think I touched on what helped me. A sympathetic GP was a very good start and the consultant I saw was very reassuring. The things that I did off my own back, in particular stopping drinking was very beneficial. In truth I have known since I was a lot younger that I did not sleep well when I had alcohol on board. That is actually conventional medical wisdom, though as with a lot of medicine, it is not an exact cause and effect and varies throughout your life. When I was younger it took a skin full of beer to have the effect but that changed through life to the point were I got the same effect from a couple of glasses of wine. It had to go and eventually I faced up to that. I like wine and beer but I like having a normal life and going cycling more. Nowadays I actually find it quite liberating and I don't miss it at all. I think we are all probably pressured into drinking more than we want/is good for us at times and I am glad that is no longer for me.
I take Amitriptyline to help me sleep at night which was recommended by my GP and endorsed by the consultant. This is an anti depressant, so has a little bit of a stigma, I certainly was not keen myself. But I was reassured by it being a very low dose, sub therapeutic for any treatment of depression. I never intended to stay on it but I still am. I have tried to stop it a few times but always seem to sleep worse again when I do so. It may be purely a placebo now, I would not discount that but for what it costs and as it seems to have very few side effects or toxicity being a very low dose I chose to run with it now. The only thing I find is that I am now just a bit more sluggish in the mornings now, whereas I was someone who could always jump out of bed in the morning no bother. That is definitely the lesser of two evils so I choose to live with that. Maybe you should have a chat with your GP about trying that. I don't think the medical evidence is overwhelming but anecdotally and I would consider myself as one of those cases, people do get some benefit.
I have not had a significant relapse for over two years now and really hope it has left me behind. I remain wary though and tend not to push myself through as I once would have done. I would not want to go through it again. Someone else at work is off with it now, following a bout of shingles as well. 4 months now and not a sign of her coming back, so I do fear for her. A hard working driven individual who very much meets the stereotype.
Good luck again.