Panda slap from deindexed blogs too - keywords are all over the place, some jumped 450 places up yesterday, others are nowhere. Nothing in the top 3.
My 3 months old website went from 2,6,16 to 36, 52, 63 a week ago. I did a recheck today: 36, 152, not in 250, not in 250...
Can i ask how many pages your websites have?How often you update them and what links you have built?
My websites have more traffic today (around 10% increased) which is not something big (its monday so i would say its normal for my niche) but they have not dropped anyway.