Stability Issues Today

I have almost never had any issues before today.

In two separate times today, I was suddenly out off a match and I returned to the main game screen.  This was frustrating since both times, the match had been going on for quite a while.

Do I lose any of my progressions, challenge accomplishments, weapon skill increases, etc?

 Also, the game has been lagging and stuttering today.

Is this because of the influx of players due to the free week?