Lets begin with some ancient wisdom. 
Do you have a realistic view of how powerful your mind is regarding influencing your mood? There is a way to find out the impact on your emotions, life, decisions, and outcomes of your behavior. Working to correct your negative thinking will ultimately create a shift in how you view yourself, relationships, events  and the world. Researches says that most people have between 12,000 and 60,000 thoughts per day. Understanding how many of these are positive and affirming vs. negative and self-effacing has a tremendous impact on your energy, life and perception. 
Through CBT or Cognitive Behavioral Therapy techniques, Mindfulness or Meditation practices, Relaxation and Fun, you can transform your mood, energy, pain, anxiety, stress via these tools. Self-care is often neglected causing fatigue, exhaustion, poor sleep and avoidance of accepting help or influence by those people who care about you. This graph below demonstrates how the CBT model works. You have a situation, develop thoughts about  it, this creates emotions and your behavior follows. Martin Seligman, Ph.D. has developed a theory of Positive Psychology to focus on strengths vs. weaknesses. In his book, Learned OptimismAmazon link to his book; Learned Optimism, he teaches you how to think to become optimistic. You can change, but you have to redirect your thoughts to change your emotions for new behaviors that give you hope, confidence and higher self-esteem.