Replying to Admission revoked

I'm a highschool senior and today i sent in my deposit to the college i'm going to next year (colorado college). I got in in December so i've been admitted to some schools for a while but i still have been terrified most of second semester that i will have my admission revoked. its not that i'm doing really bad or anything, its just that i feel like i havent really enjoyed being a second semester senior to the fullest because i've been too worried about getting my admission revoked. So my question is this: does anyone on NS have the experience of getting your admission somewhere revoked and if so how significant was the drop in your grades?