I really wouldn't worry about it. Got my class one a few months ago, doc asked me loads of questions bout it but didn't even make me run around the car park. If you're really worried about it, have a quick puff of your ventolin before you go in to do the medical. The blood test is only a pinprick on your thumb for hemaglobin levels and the urine test I presume is for sugar/glucose/drugs (I presume) so it won't show up in any of the tests an it'll make things a little easier for you!
