This morning I just entered my insectoid colony (where I had declared independence a few days earlier and built a lot of stuff afterwards) only to find out that it had sent me back to a previous save (it was defenetly not the one just before the last save because the game that loaded was far before the moment I declared independence) and I lost at least 4 or 5 hours of progress.
Android 6.0.1; galaxy A5; my colony version 0.54.1
Make sure you have a reliable Internet connection. Check your device for files with an .mcb extension. The .mcb files are backup files made by the game and you may or may not have them (depends on permissions).
In the future, after you make a lot of changes, make a manual backup of the colony. This has saved many people, including myself, hours of work on the game. You can make a backup by returning to the title screen, choosing "More Options", then "Game Data".