Daisee the initial telling was a massive shock for my kids. They cried. But later on that day, huddled under a duvet together, DS, 11, who isn't emotionally mature at all, but had seen lots in the last year as around more, came out with some really wise things. DD, 14, usually wiser, who'd been away for the last year, found it more of a shock because she hadn't seen how bad it had got.
I'd suggest get some comfort dvds in, hot chocolate, warm duvets, some comfort food. Cancel anything stressful elsewhere. Consider pulling a sickie and having a duvet day or three. Its like a bereavement, the outside world can wait.
I think it helps to think concretely what might change for the kids and what not and get the story as straight as possible first. e.g and we will be staying here till the summer, so you will still have your bedroom, but then things might change, but I will let you know as soon as things are clear. For ours absolutely everything changed (schools, countries, friends), so there was a great deal for them to absorb, a tidal wave, and I think it matters to get your comfort where you can.
But sometimes, we just need to tell the truth, bleak though it is. I have lots of friends who avoid telling bad news and avoid you when you are going through bad times. I am so clear this isn't a good way to be! There is a clarity which comes from telling the truth, painful though it is. Good luck, am thinking of you.