It's a weird thing, you never know exactly when the 'holy crap, I'm moving 4000 miles away to an entirely new country' feeling is really going to hit you. You know in your head that you've made these plans and that you want to move and start a new chapter in your life, but there's still that part of you that goes, 'crap, am I making the right decision? Am I ready for this? Can I really leave everything I know and go to this new and other place?' Or maybe it was just me?
It's a very disconcerting feeling and made my move so bittersweet. I couldn't wait to move here to the UK to be with my guy and to start our life. I'd been saving up to make a big move anyway, it was never planned to be quite this far though...
I spent as much time as I could with friends and family in the two months leading up to my move. It probably helped that I was able to not work for the last two months in the States. We got to spend a lot of time together and make plans for how we would keep in touch. I probably ate my weight in American food I can't get over here. Jars of Claussen pickles. Too much Wendy's, Taco Bell and Chik-fil-a, Chili's, Village Inn pie, and Smartfood white cheddar popcorn.
I suppose what I'm saying is, spend as much time as you can with those you love and do everything you love doing as often as you can. You've got this! What really helped me was remembering: You've done your research, you know what you're doing. And the best thing is: this is only as permanent as you want it to be.
Talking with your significant other and your closest loved ones also helps, they aren't going through quite the same thing as you but they sure can understand! (Though, if I remember right, you're husband is working to get Irish citizenship but has been a US citizen til now?)
Sorry, this became a bit of a ramble.