Been there and got the t-shirt! Suffered really badly last year which started a couple of months after my op, something else must have been out of kilter which caused it. I've always been a bit nervy on my own at night when OH is away but then it got a bit out of hand.
It all started with a turn of vertigo which I'd never had before, woke up one morning and the room was spinning and frightened the life out of me. Then I got really worried about turning in my sleep! Then one night I was just lying there reading and my heart went crazy, took ages to settle and ended up sleeping semi upright. Then of course you associate bedtime with all this and it's even harder to relax and sleep properly!
I know what you mean about the shallow breathing Sparkle, desperately trying to deep breathe to get calm and you feel like your lungs just won't inflate! And the dreams, jeez they ware you out sometimes!
In the end I found that playing some relaxing music on my iPod along with playing a word game distracted my brain enough to drop off. It's funny playing this game as you wouldn't think that would happen but it's better than reading a book! The other thing I found useful was a distracting mind game, bit like counting sheep but more complex so start with A and say a name, eating or doing something and in a place. A friend suffers with bad anxiety and she gave me the useful distracting tips.
I was usually okay once OH was around but even now I still get a bit of the old anxiety stuff at night. I think it's partly because during the day everyone is around, awake, help is near but night, people are asleep, nothing's open etc. The night I had the really bad palps I really didn't know what to do, should I call the emergency services but then thought it's not really an emergency but then by yourself at night then fuels a panic situation....it's horrible!
I was pleasantly surprised last time he went away as I was waiting for the anxiety to kick in and it never came but then I'm much better now and hormones have settled down again, so I do think it is hormone related.
Try a sleepy tea at night, night rescue remedy and spray lavender on your pillow, all good stuff for trying to keep you calm. Hope you get to drop off but try not to let it grow into a habit as its then hard to break. Take care ....