My name in chinese means what!?

Here's my problem: Everytime I introduce myself to someone they laugh. At first I thought I had mispoken, but I checked with my teacher a hundred times, making sure I had the pronunciation correct, that i was saying the right phrase, at the right place, during the right time. I tried again and again, but they still laughed. What could I be doing wrong? I mean, I have come to terms with the fact that everything I say is going to be slightly wrong, and that few people will understand me well, and I would have let it go, but they were CACKLING, rolling on the floor, their faces red, their bodies convulsing with an overflow of hilarity.
What is so funny!? I asked, my voice calm, almost hurt sounding. The three girls I had confronted continued to giggle tremendously. They reminded me of when I was in fifth grade, and three of the popular girls had found a poem I had written. These girls had a secret, something they didn't want to tell me, didn't want me to know because it was so much funnier if i was clueless.
Finally, after much pleading, bribing, and down right begging I found the answer... Ben, in chinese means stupid. Every time I said "Wa shi Ben," what they heard was, "I am stupid."
I now go by Benjamin.