Actually the vast majority of ppl in Brussels are native French speakers, and all the Dutch speakers master French very well. Which is why at the end of the day I never get the chance to practice Dutch so thank God for TV and the Nederlandse Akademie. Im sure you didn't do any worse than the average freshly arrived Eurocrat, though.
Jeeks, I would say that they aren't any colder than the Swedes. However the Swedes' coldness is kinda relaxing, while the Belgians' (or at least the ones in Brux) is somewhat stressful.