Game Running Poorly

The game does sometimes run into performance issues, but I wouldn't conclude that it's completely the game until checking a few things. Having a large tray folder (library) can cause problems for one. Having more sims in your world than your hardware can handle, having sims or households with a lot of items in their inventories, and using mods or custom content can all affect performance. If it isn't any of that, try running a repair on the game. Of course, don't forget to check that your hardware meets requirements and that your drivers are updated.

If this all fails to point you towards a solution, then yes, it's probably the game. I wish I could say whether or not I've been seeing the same thing, but I haven't been playing lately.