Meet with your academic adviser. He can help you assess your academic and career goals. If your poor performance is the result of a lack of interest in your classes, for example, he might be able to recommend a major that is more suited to your abilities. He also can give you a better sense of how your course of study relates to career possibilities and connect you to university resources, such as individual tutors and writing workshops.
Participate in an Academic Success Workshop. If your GPA has dropped below 2.0 and you are on probation, this might be a requirement for you to stay enrolled. In the workshop, you will learn about the university's policies regarding academic performance, strategies for better studying, and how to create an action plan for improving your grades. These workshops are also designed to help you understand your academic strengths and weaknesses, and to provide you with a support system.
Meet with each of your professors to explain your situation. Tell them that you want to work out a plan to catch up on your assignments and finish all required coursework. They may be willing to grant you extensions on some assignments, and you also may have the option of taking an incomplete, or reducing your course load by dropping some classes. You can also meet regularly with your professors during office hours to talk about material covered in class and learn their expectations.
Form a study group. Divide up the material each week, or rotate leadership so that everyone participates equally in preparing and teaching the main concepts to others. Go over your notes from class, and drill each other on key facts. Meet at the same time each week for consistency, and limit study sessions to less than two or three hours.