MASSIVE: Emilia Clarke, aka. Daenerys, says goodbye to Game of Thrones! What could this mean?

Emilia Clarke, who plays Queen Daenerys Targaryen on mega-hit HBO show Game of Thrones, has posted a sensational tease that appears to indicate that she has concluded her role.

Taking to Instagram, Clarke, who has been an everpresent on Game of Thrones, has written:

"Hopped on a boat to an island to say goodbye to the land that has been my home away from home for almost a decade.
It’s been a trip @gameofthrones thank you for the life I never dreamed I’d be able to live and the family I’ll never stop missing #💔#lastseasonitis"

Dissecting this, the most obvious interpretation is that her part in filming Game of Thrones has ended, which is a surprise given that the final season isn't expected to arrive till next year.

Here are the possible calculations that arise from Emilia Clarke saying goodbye to Game of Thrones at this stage:

1. Given that Daenerys is one of the main characters, one would think that she'd play a part in each of the six rumoured feature-length episodes of the final season. If this is the case, and knowing that things are about to converge, it's a reasonable estimation that filming may have ended or is about to end for everyone.

2. If filming is really about to end but the season will only come out in 2019, it could mean that there's heavy post-processing involved. This is not exactly a surprise. We know there are wars with thousands of fighters, extensive use of Dragons, werewolves, giants, mammoths, (Ice-spiders?) and such to come, and post-processing does take its time, but the big question is 'Will it take a full year?' 

Game of Thrones generally comes out during May-June, but will fans really have to wait till then? Is it possible that the final season could come out really early in 2019 -- winter instead of summer/monsoon?

3. There is at least some suspicion that George RR Martin is holding off releasing the next few books in the A Song Of Ice And Fire series on which the show is based till after the show has ended. (Some speculate that he may give the books a different end -- a twist worthy of Martin!) However, if filming has ended and if the show comes out by early 2019; and if it takes about 4-6 months publishing time for a release of the expected magnitude of Winds Of Winter, are the books back on the table? 

The previous book, Dance of Dragons which is book 5, came out about when the first season of the show did. 

What's your view? What does Dany concluding her filming mean?