Not surprisingly, there is a high correlation between class attendance and grades. You might be able to make up the assignments and avoid the loss of a grade. It is more effective to set aside 1 hour per day than trying to do it all at once. Find someplace quiet to study and focus on the task at hand. Attending college is a full-time job, so 40 hour per week is not unreasonable.
Time management is essential.
Review your notes on the day you took them and again before the next lecture. Add comments and questions to your notes while the material is still fresh in your mind. Plan to ask me about any points that are not clear. The University of Guelph has specific suggestions on effective note taking . Study the material in the text before it is covered in lecture.