Am I going to have my admission rescind?

I think universities hold the threat of a rescinded offer of admission over students' heads more to put the fear of God into them than anything else. I have never heard of any school rescinding someone's admission, just as I have never heard of a high school student not contracting senioritis his/her last semester/year. Yes, the C- is bad, but I think your overall GPA is better (3.381 vs. 3.333). Don't sweat it, if you've already made it in with a B+ average, congrats.