My first year of college I took a General Chemistry course that was designed to weed out the students who didn't have what it takes to get a science degree.
The first day of lecture, the prof said "If you don't already have the entire periodic table memorized, you do not belong in this class."
There were 300 students in the class, half had dropped out by the first mid-term.
Each day of lecture was one chapter of Linus Pauling's General Chemistry. That is a 1,000 page textbook, full of problems. All of it was very math intensive, and you had to take calculus parallel with the chem course if you expected to get through it, because the calculus was used in the chem and the courses were synchronized.
Lecture consisted of writing as fast as I could, everything he wrote on the board. And he was fast, and would not stop for questions. If you had any questions, you had to go to his office after class.
In the evenings, me and 3 others would spend 3-4 hours going over it again. You had to read every chapter in advance, or there was no way you could hope to keep up with the lecture.
Try to get a study group together and meet up in the evenings after class- it helps a lot when you have a fast-pace course like that. And if you have to miss a day, you have someone to help you catch up.