I work a tech job that has extreme crunch hours for long periods of time, so I feel your pain! It does make it so hard to stay active. One thing that helps me is exercising during my lunch or supper break. Does your company have a gym? Can you close the door to your office and do some online exercise videos? Can you leave the office for a half hour and go for a jog, or even just a walk? Or is it possible to take the conference calls at home, so you can go home and work out before the call?
Hope some of these suggestions help. I get where you're coming from, though...it's especially difficult to get motivated when you're working long hours, because it's so tiring! But you've come so far and I know you'll find a way to make it work.
Good luck!