I just started my diet yeseterday and I weighed in at 191.6 lbs 18% b/f according to my log on FitDay , now I am 189.4 lbs with 17.5% b/f. Is this possible?

I have been eating pretty good lately, but I wouldn't think THAT good.

Should I be very careful or what? Am I in danger of losing muscle mass??

Today here are my figures..

~2,020 cals
97gs fat
106gs carbs
178gs protein

I didn't work out today either. I wanted to take 2 rest days before I went back (I hit chest monday, legs tuesday).

Any advice is greatful and of course appreciated.