My ex and I left for the US in 1978 with our 20 month old son leaving a doting Granny behind. I felt so guilty as she adored him and I was taking both him and her DS to N.Y. Now I'm back here , since 1984, divorced with 2 kids. Now I have 2 DGDs and one of my 'dreads' is them deciding to move abroad. The US isn't so bad as it only takes about 7 to 9 hours to fly to the eastern side - but Australia is such a distance away. Do you honestly think they will stay for such a short time? We went for 18 months, I lived there six and half years and my ex is still there, married to an American woman and an American citizen.
Thank heavens for Skype, e-mails and Facebook. I used write loads of letters which could take 3 to 14 days to arrive in the UK and often cross each other so news came in odd amounts. My parents left the UK in 1947 when I was two and half and returned 7 years later with me age 9 and my brother 6. My mother hadn't seen or spoken to her mother all that time - and they were very close. Flying out for holidays then just didn't happen as it was very expensive and took ages - no jumbo jets at that time. Sailing took weeks depending where we were posted.
So you can contact each other far easier, send your little one little letters for her, ask for loads of photos on any e-mails sent, and if you can, go out again for another holiday. I hope you are feeling better now and trying hard to be brave, I so emphasise with your feelings now I'd be devastated.