Right Choice?!

I'm sitting here thinking, should've i NOT had the fat free sour cream as a dip for dinner?!

We were invited to dinner at my mother in law & i took my roasted chicken with me. She had full fat plain yoghurt or the fast free sour cream. I went with the sour cream for a change. But now i'm doubting my decision. I'm now worried about the scales tomorrow. Would the sour cream have a big affect on my weight? Would it have been better if i had the yoghurt? hmmm .. better read more on the Dukan Diet!