I find that I am very sensitive to caffeine. While decaf does have some caffeine in it, I'm usually OK with it. However, the last time I got what I thought was a decaf, I got very jittery and anxious and had a lot of trouble concentrating. I'm 99% sure that I was actually served a caffeinated coffee and not a decaf because I have never had that reaction to decaf before. Is there any chance this could have happened to you?