Any specific books that helped you study?

Hi, I am in my first month of anesthesia school and I am starting to get discouraged. I have done well on my first two test, however, the third test was awful . Even though the class average was low, I still think I should have done better. I felt prepared for the test when I went in, but my grade did not reflect this. Our professor told us to re-evaluate our study methods. So, I was wondering if there were any specific books that helped you SRNAs or CRNAs study? I have been reading, studying with groups, making flash cards, and recording/listening to the classes. She teaches from Stoelting(Pharm&Phys) which I feel it is hard to break down the content. Any advice would be appreciated. Thanks!