Are you playing in the world that came with Island Paradise? That world is particularly laggy. See here for some solutions:
http://sims3.crinrict.com/en/2014/02/lags-in-islo-paradiso.html
In general there are a few things you do if your sims are freezing. There might be a sim stuck somewhere in town and the routing failure causes problems. Try the cheat resetsim * to reset every sim in town.
There are mods that can help you too but I'm not sure that we can discuss those here. You can see some tips to help with the issue on Crin's website:
http://sims3.crinrict.com/en/2011/04/bug-lags-intermittent-freezes.html
Caspin
Do not have Island Paradise expansion. I have Showtime, Master Suite, Supernatural, Seasons, 70s 80s 90s Stuff. I hadn't installed any CC, and/or items from the exchange. It just started lagging all of a sudden. I will try your suggestions though. Thank you for answering!
