When you say "there are other things going on" with your body... like what? Your doctor needs to consider all of those factors - not just the weight, though 40 lbs in one year seems crazy when you are active and watching your intake.

I have an autoimmune thyroid disorder, and it can lead to weight gain/difficulty losing weight, but there are other effects as well. Get a list of ALL of your issues and see your doctor again - or see a DIFFERENT doctor. There are VERY simple blood tests that can determine if something is going on that needs treatment.