Balance and Stress Management

So in the last week or so my job has gotten extremely stressful, to the point of having chest pains. I work on Government Contracts and this is the start to the fiscal year end crunch time. I have come to the conclusion that I am not managing my stress properly. In these high level stressful times of the year my perfectionist side, and my need to be all, and do all for everyone just doesn't work. I have a hard time saying no as I want to get everything done. So this week I will be researching and reading what I can to try and bring more balance to my days. I am making a vow to myself to walk everyday during work to get that much needed mental break. How do you manage your stress? What do you do to find balance?