The advice on how to handle it from others is awesome - in terms of career advice. I'd like to also add that you should "get out more".

I've had experiences almost exactly like yours. Long hours, lots of pressure from above and below.

I have found that leaving the office and wandering around our neighbourhood for a few minutes (<=10 && <=30) when I'm feeling loaded really helps clear the brain.

What's neat is that when I come back I can usually find one thing I need to knock out from my massive list and close it, done well. It's like I come back with clarity and energy. Of course it depends on making it from the door to your desk before anyone says "do you have a minute?" - then it all goes to heck for me.

I also "escape" at the weekend. Clearing head-space like that puts you in a good mood, lets your sub-conscious solve some of the issues.

Happy people are better workers. Remember that for yourself and more importantly for the team you manage.