Intro & sound lag after installing new pack??

I wonder if anyone can help. I was playing the Sims 4 yesterday absolutely fine, no issues whatsoever as usual. However, this morning I decided to download the new pack. Since then, I have tried loading into the game a couple of times and it works, but there is an insane lag on the intro screen, and when I load into the default household, the sound lag is unreal. It sounds as if I've got the playback speed turned all the way down? 

I thought I'd play in the default household for a few minutes to see if the gameplay itself lagged, and no lag for the camera movement, sim movement or anything. But it is thundering in my game currently, and even that sounds like the playback speed is turned down. It's so bizarre and I've never experienced this before. 

I did remove my mods/cc & saves and repaired the game, loaded up again and it was still the same. I deleted the localthumbcache as normal too. I also have the up to date GPU driver installed too. I ran my Overwolf programme which shows GPU & CPU usage whilst in the game, no big surprises there, all looked normal. It's just as if the game is suddenly not loading up correctly and causing the intro screen to lag and the sound. I don't have any lag on the loading screen after the intro screen either.

The EA app however did crash twice and asked me to restart, so could it have anything to do with the EA app as opposed to the game itself? 

Any advice??