Discover what you want. You can have more energy when what you're doing leads to what you want.
Many students quit school simply because they are unclear about what they want.
Writing it can make it clear. Record the specifics. Observe your actions and record the facts. If you spent 90 minutes reading a spy novel instead of your anatomy text, write about it and include the details, such as when you did it, where you did it, and how it felt. Notice your inner voices and pictures.