I have an issue, and I have absolutely NO idea why it suddenly occured and how to fix it..

I played the game for a week or so with no problems at all. Suddenly when I wanted to play, I started the game, but uplay stopped working before the game even launched. Then I tried it in offline mode, the game started and I could play, buut after two hours of gaming.. I couldnt F*CKING save....!! I have tried several times, with the same result.
I bought the game from Ubisoft, no cracking or any illegal sh*t.

This is all I know. I have no idea what to do, so any help or tips will be appriciated.

Siincerely, a dissappointed gamer who really looked forward to playing Far Cry 4.

Thanks. ^^