FOV pans in and out while walking

As above with the added bonus of the movement speeding up and slowing down continuiosly.

 

While swimming I forced to dive, its almost as if down key is bound to the walk key .

I have a GTX 10600 ti

AMD FX 8350 processor

16Gb of ram.

Ive searched for similar problems here but wasnt sure if it was actually the same.

Is there a fix for this? I find the game to be unplayable right now.

 

Many thanks

 

PS please accept my apology if this does turn out to be a duplicate issue