Feeling like I'm drowning in the work

I may say this every quarter, but this seems like my hardest quarter yet. I have not done well on any of the tests and I can't figure out why. I've never had the thought in my mind that I might not pass a class but I am having those thoughts now. I hoping by the grace of God that I can make it through the next 8 weeks. Her tests are quizzes that are worth 15 points every week. The problem is there are usually 13 questions covering well over 100 pages of reading, and she makes them up. They are not out of a test bank and figuring what she 's looking for has turned out to be difficult. If you miss three, you've pretty much failed the test and the average needs to be a 79% Doesn't seem that bad but with such high stakes questions the stakes are high. I've never had a class like this. I'm just praying, praying , praying and working so hard I don't know what else to do. The constant stress level in starting to get to me and I don't stress out easily.