(1) In times of emergency and stress, remember that the two basic principles are to make sure you eat well and make sure you get good sleep. These can hardly be overemphasized. You don't need hypoglycemia and sleep devrivation to add to your troubles. Two tablespoons of brewers yeast per day will help immensely, since yeast is packed with B Vitamins (the "stress vitamins").
(2) Also useful in times of emergency is continuous breath. It helps to clarify your thoughts and feelings, and it recharges your energy.
(3) Feel your feelings, as painful as they may be. Talk with your friends, and possibly with a counselor. You need people who will listen and empathize without judging or criticizing. Helping you with suggestions isn't generally helpful. "That must be tough," is helpful. Don't make major life decisions when you're under stress.
(4) Keep yourself and your environment clean. Letting things slide won't help. Get some exercize. Get some sun.
(5) Remember that all things pass. You won't be down forever. If you're down now, you'll be back up again. Losing hope isn't realistic. Keeping hope alive is one of the most important things you can do.
(6) Use problem solving skills. Any challenge can be thought of as a problem and addressed.
(7) Use your spiritual resources, if you're a spiritual person. Prayer, meditation, contemplation. Going for walks in nature. Going to church, satsang, puja, darshan, sweat lodges....
(8) In times when there is no emergency, the rules are pretty much the same. Eat a nutritious diet, and get good sleep. Stay on top of personal hygiene. Talk to your friends, use your personal support system. Learn anger-management skills and stress-reduction skills if you need them. Have dreams and go after them.
Here's a version of Self Care Skills you can download: