I have noticed recently that high school years has so many bugs. The classes take ages to actually start and the day drags on and the sims lag out. I have tried without mods or cc and it is still the same. The Sims just take ages to actually start moving and taking action. Been like this for a couple of months now.
Edit By crinrict: Added Tag to Title, Adjusted Title, removed unnessary thread tags. Please only choose the ones that actually apply to you and the bug at hand.