My daughter moved from UK to New York about 6 years ago to work. It was a great opportunity for her and intially she thought it would only be for 18 months to 2 years. But obviously 6 years later she is still there, and has met a lovely man is is getting married in August. So I have to resign myself to the fact that I am never going to have her around the corner to meet up with for a coffee and a quick chat.
I felt devastated like you do now, it was the first thing that I thought of when I got up and the last when I went to sleep. It gets easier, as everything does with time.
We have managed to visit her 3 times in New York, and she has been over here at least twice a year including Christmas. We Whatsapp to each other often and Facetime whenever we can, but time differences can be restrictive.
It will be as hard for your daughter to leave you, regardless of what their dreams are, it is a trade off, so there will be many tears from everyone, but be proud of the young lady she has become and how strong she is to pursue her dreams.
There will be family times you will both long to be together, but make sure every time there is a family get together you Facetime/skye each other. My daughter Facetimes with her 21 month twin nephews, and they laugh and chatter to her in their way. Makes the world a smaller place (well just a little).
On a personal note, my daughter has made two trips over to the UK in the last week, because her precious cat (who lives with me) was very poorly, and very sadly went to sleep on Wednesday. Emotions are very raw at the moment and she is heartbroken, and at times like these you just want to put your arms around them everyday, but she had to go straight back to NY.
Start planning your first visit to her, find yourself something exciting to do/go to a couple of weeks after she leaves, keep yourself busy.
I am sending you a big hug and your daughter very best wishes on her new adventure.
Sorry this is a bit long winded, I do go on a bit!!