The sims are stuck and I can't speed up time or pause it! Help!

Hi guys, lately my game freezes out of nowhere and I can't change the acceleration or really pause it, I have to click several times until it works.  Sometimes when I want to pause I click and the sims continue doing the actions :( Please does anyone know how to solve this? What is the reason for this to happen? Even without the mods the same thing happens! Someone help me pleaseeee :(((