I had a similar problem to this with high school years pack and all I had to do create a new save. It may just be the save you're using that's corrupt or is not working with the pack. Even on the new save it may take a few days or a few times opening the game for all of the items and features to show up. If making just one new save didn't work for you, you may have to create one or two more saves and see if those work. If you haven't tried creating a new save then you should try doing this.
I have the same issue.
I tried what @Lani_Elyse said, but after four new saves, the world still won't load for me.
It's bugging me.
Same with mine I finally broke down an had my son uninstall everything an reinstall an I was cringing cause alllll my mods I downloaded are gone so I will have to spend a whole day doing that! Lol but it finally showed up
