I'm feeling the same way myself, thanks to sleep issues, stress and some other health issues. It sucks. The best I can say is to eat a good balanced diet with plenty of veggies and lean protein and take a multivitamin, fish oil and a good probiotic on a daily basis. This will at least help you to look as healthy as possible given the circumstances. For many people, a good diet and supplements can help with depression and insomnia, too. Sometimes being difficient in vitamins and minerals can cause dark undereye circles, so that can just make matters worse. It's all inter-related.