Issue with Lost Households and Careers in The Sims 4

When I try to play The Sims 4, sometimes I log in and all of my households are reset and have disappeared from the worlds. Fortunately, I saved the households as 'Save As,' so everything isn't deleted. I somehow managed to restore the households. Why does this happen? It's frustrating because some things I haven't had time to save get lost when I only click 'Save.' Careers also disappear from some sims, even if I save as or save. Help, please