Hi Aynsliee,
Try a few troubleshooting steps before uninstalling anything else.
01.) Does this happen with a new game? If not, it maybe just that you have a bloated saved game. - A game that maybe too-large or too buggy to load. This happens from time to time, specially if you've been playing it for a long time.
On my older computer, it would actually "freeze" at almost full loading bar. It took it about 8-10 minutes to load. Specially with games that I had been playing on for a few months or more.
02.) Have you tried turning off Interactive Loading Screens? -- Go to Options (...) Select the gear tab, which is the General Settings, at the bottom of the menu uncheck the box labelled Interactive Loading Screens
Turning this off will help the game run a little more smoothly as well.
03.) Turn off Memories -- Go to Options (...) Select the gear tab, which is the General Settings and look for the word Memories and in the drop down menu select Disable Memories.
While your in this tab, it may help to make sure Enable Shop Mode and Lessons are un checked.
Turning off memories means less game bloat/overly large game save file.
04.) Delete Game Cache Files - (See link below)
Delete the Game Cache Files
http://www.carls-sims-4-guide.com/forum/index.php?topic=20732.msg401809#msg40180905.) When ever my game becomes buggy, I do a factory reset. That seems to fix most problems. It's something that maybe worth a try.
[This is different from a total-game reinstall - This just sets the game back to factory default.]
Move your Sims 3 folder to the desktop or some where safe, and rename it something like Sims 3 Current. Click the Sims 3 icon to create a new Sims 3 folder.
Go To: ----> My Documents > Electronic Arts > The Sims 3
If you want to continue to play your previous game-saves, go into the Sims3 folder that you backed up and copy over your game saves, files and such over to the new game to see if that helps.
I hope this helps,
MrsFlynn