Game is frozen and I need to save Sims 3

I have a huge problem I that is driving me up the wall: My Sims game keeps FREEZING! I don't want to close the game or I will lose hours of progress that I've made and it will take forever to get that precious time back, and it will never be the same as it was! Sometimes it freezes during CAS and sometimes it freezes in-game, and sometimes it freezes when I was on my player wall and clicked the close button to close my player wall. Sometimes music keeps playing, and sometimes it doesn't, and sometimes it plays for a long time and eventually stops. I don't know what to do to fix the game without closing it and I CANNOT LOSE MY PROGRESS! I NEED TO SAVE SOMEHOW! Please HELP!!!