School.... AHHHHHH!!!!!!!

SO... last week I started school again.  I have been graduated for 4 years and I am now going back.  I am taking only one class, anatomy/physiology, and I am already dying!  I took my first test on Saturday I got a 77% which does not sound so bad but get this... I had 30 minutes to answer 30 questions I guessed on 70% of the test because I had NO clue to the answers, and then I went back through and used my book to help me find the answers to the 70% of questions I did not know the answer to.  I got to question 12 and time ran out, so I guess I am a really good guesser!   I just hope the rest of the tests will not be that hard because, I have a feeling my luck will run out and my really good guessing will not cut it.