Why do I sometimes feel so incredibly weak for no reason?

Many people feel weak because you may not be eating or sleeping enough so drink, eat, and rest more. If that doesn't help than talk to your doctor and see how they can help you out. Your parents are also there to help you. Follow their advice and see how it makes a difference in your life. Not to mention, if you have a friend, family, ember or even an acquaintance with anyone who you know struggles with them help them out to. We can make a great difference in this world. So Lets help each other out.