Although we prefer not to think of it as such, parenting is a job in that it is a critical task in our society. What comes with parenting is sometimes terrific stress, and one is forced to keep ones composure many times, for the sake of the child. How should parents deal with the many stresses that arise in ones life is the big question.
Here are some key suggestions to keep your head about you:
1. Work an  exercise routine into your schedule. It doesn't even have to be at the gym. A simple floor workout in the morning can help you get your circulation going and thus help reduce the stress in your day.
2. If your feeling overwhelmed sit down with your spouse, and see if there is any task that they may be able to take over for you, even if it's as small as having them keep the children amused for a few minutes while you do something for your self, go for a walk etc.
3. Don't overschedule yourself or your kids. No extra activity is worth your sanity.
4. Make sure you find romantic time with your spouse, even if it's a couple of times a month. One periodically needs to reconnect to keep the fires going.
5. Find a network of parents in the area to get support from, even just for social reasons. This is definitely a must for stay-at-home parents. It gives you other adults to talk to, and share ideas with. As much as you love your kids, you can't survive with goo goo talk all day.