I had that problem, along with several others, and for me, I had to uninstall one of my expansion packs and delete some saved games. It was just too much for my computer, it couldn't handle it all. It is an old computer and I bought it for school work, not for playing games.
How many expansion packs, world (store) towns, store stuff and such do you have and how powerful is your computer? How many saved games do you have? I didn't realize that there was a limit to how many games you can save, depending on how big the file is. I have around 40, but most are small ones, where I created sims to used as mates when my sim can't find one in a town that I am doing a personal dynasty.
Doing project stories, I have created some "seed" families, three for each town, with seven towns, that is 21 files, but they have just the family and the kids they had, at toddler stage. The others are from the three project families and a few others.
If you have a lot of saved towns, with them (files) being quite big, then that could be your problem.
Do the clean cache as suggested and it that doesn't work, look at what you have on your computer and see if it could be too much for it to handle. I don't know what type you have (what I know about computers would make a small paragraph), how many expansion packs and such; but that could be part of the problem.
Either way, you have lost anything from after the save. If you saved your game before you left and didn't save while in China or one of the other countries, you can go to your last save. If you saved from in China, they you will have to go to an earlier save and will have lost from the last save.