I had (and still have, sometimes) the same exact fears! I didn't get sick at ALL at first... none of the bad reactions they said would happen happened and I would stop eating when I felt like I didn't want the food anymore but I didn't even necesarily feel Full, you know? Not like I expected I would. the doctors just said that was good though, and I guess it's working properly, they tell me it is
Just be glad you're not getting sick!