"Muddiest Point(s)"

When I walked into the classroom on Friday, I thought I was going to do really good on the test.  I felt like I knew the material really well.  The first couple of pages were good and I felt like I knew what I was doing.  But as I got further and further into the test, it seemed a lot harder and I felt stupid.  I have no idea how to do the Farmer Ted problem and when I ask other students for help they tell me that they don't understand either.  I used to never have to study for math and now I have to study all the time.  This class is easy when we're working together/individually but once I get to the tests I'm awful.  I don't think I'm a terrible test taker. Maybe I'm just stressing out too much.  I dunno....