This is a scream. My doctor asked me in October if I could lose 42lbs by the second week in January (13 weeks away). He then went on to tell me not to try to lose more than 2lbs a week.
Apparently this one can't! Actually, I find it so very bizarre that your doctor would give you a date that is so close and expect you to lose such a massive amount of weight? Maybe your doctor has two personalities? One is rational and one is not!
I've never once had a doctor bring up my weight. Either I'm going to the wrong sort of doctor or they could sense the sort of response they'd get from me :P
Maybe your doctor left his brain out to lunch that day...