sims 2 university all progress gone after reloading into family

i played today with this one family for like 3 hours straight, i made a lot of progress with 4 sims and they were already in the final semester of uni. i saved the game, went back to main screen because i wanted to put a cheat code boolprop testingcheatsenabled true, just so i can help my sims with their needs and once i went back into the family again, the whole progress was gone and they were all back to square 1. i am so so annoyed! i saved the game and it still erased the whole progress.... this needs to be fixed.