St John's Wort has helped many people to prevent, or cope with this problem. The principal ingredient is hypericum which helps lift mood in most people. It has actually been marketed as a drug in Germany and is approved for use.
The oil made from St. John's Wort can also be used for healing wounds.
It might be worth consulting your doctor before embarking on a course of treatment although there have been few reported side effects. A qualified herbalist can also offer advice.