I can understand how hard you are finding this at the moment, It can seem a shock, and for a while you cant see past that. But perhaps you can start to think of being a grandparent in a slightly different way. You can look at all the various things like whats app and ways of keeping in touch. Not making it into a rigid has to be kept to time, but evolving patterns, so that you might speak to each other on the phone every week besides keeping up with various emails and perhaps your son could also manage to have a contact time with his sister regularly. As others have said , you will be able to visit them at times and I think the idea of a b/b would be great to allow you to have time together and also a little time on your own to do something you enjoy. Perhaps you might keep a notebook, not a diary , but a book that you just put in what you have been doing, what changes are going on in your home etc., which in the future might be interesting for both your daughter and your grandchildren to read , and remind you when you look back too,of different things that you have been doing. As your grandchildren grow, they will be able to talk to you and send you messages and I know it will be a different kind of relationship to being close by, but it can be something special. When I lived abroad I used to write letters as and when I had any news about what I was doing, what was happening such as special days or the harvest or whatever. These letters my mother kept and I quite enjoyed rereading them and being reminded of what I had done all those years ago.I do hope that you will get over the first shock and then be able to start to think in a different way, about how you will be able to keep in touch and in time perhaps even come to enjoy some of the different things, and places that you might visit near their new home. You will always be mum and granny, wherever they are or you are, and I hope you will find a way to keep up your relationship in a very different but still important situation.