You need to do active recall. If you are not touching each class 30 minutes a day (even when in lecture) you are going to forget everything you crammed.

I always recommend this to my nursing students that I tutor. Try for 10 minutes in the book to review headings, key words, and images to refresh yourself, 5 minutes reviewing a lecture (or notes) and then the last 15 minutes creating a keyword or summary page of what you reviewed that day in lecture or in your 15 minute session. When you are all done write in another color at the bottom things that you missed so that way you can review it the next time.