Graduate school is doing research, research, research. You will read a lot of journal articles and books, conduct experiments, and do lots of writing.
Many students also work as research or teaching assistants to earn a stipend.
Graduate school isn't for everyone, but there are some ways to help you identify whether it is the right path for you to follow. The first step you should take is to get involved in research as an undergraduate . Commit to a minimum of one year in their lab. The more experience you get, the better you will be able to identify what you enjoy doing, the more exposure you'll get to the different aspects of conducting research, the more advanced research tasks you'll learn, etc. In addition, ask other graduate students about what it's like to be in their doctoral program - both good and bad experiences.