Same thing happened to me only my score was an 89.3%. I was mad beyond belief. I redeemed myself in orgo 2 and made the A. Make sure you do the same. Don't feel to bad your not the only one. Congrats on a great semester!
Because we are all in the same boat vying for a limited number of spots in a highly selective process. I don't use twitter, but I do use facebook - however, many of my FB friends will not understand why I am upset about a B. The people here are far more likely to have similar experiences and therefore can sympathize with the frustration.