Life is stressful enough on it's own, but when you add in medical problems it just gets even more stressful. There are two very simple ways to keep yourself healthier, thus keeping yourself less stressed. If you eat right, as in a healthy diet following the USDA's MyPyramid (the cute little pyramid that tells you how much to eat of each of the five food groups) and stay fit with regular exercise (as in at least a half an hour of vigorous activity at least 3 to 5 days a week) you will feel better physical AND mentally.
Fitness is easy to get, if you think about it. Walking is fitness, so take a half hour walk 3 days a week and you've got a less stressful future on the horizon. If walking isn't your thing then jog or join a gym. Too many Americans are over weight, obese even, and it's because we don't get enough exercise. We drive our cars everywhere, or ride the bus and we spend way too much time sitting on our butts on the couch watching TV and eating junk food as our butts get bigger. But they wouldn't be getting bigger if we'd just get up and get moving.
We Americans are also getting over weight and obese because of the foods we eat. We're busy, on the go, so we swing by the closest fast food joint and get ourself an 800 calorie lunch, full of fat and grease, when we could be eating a healthy sandwich and a salad for less than half those calories. Watch what you eat, keep a food diary and pay attention to how eating certain foods makes you feel because some of the food you are eating could be causing your stress levels to rise.
And as a wise rule to follow for anyone, cut down your caffeine, salt and sugar intake as much as you possible can. They are all very tasty but also are very bad for you in any kind of excess, even minor. Don't keep yourself from ever eating the things you love again, but if the things you love are mostly bad for you try to eat them less often and less of them. You body will thank you and your mind will too!