Hey, I took the course last year. Don't worry too much about feeling lost during the first couple weeks of classes - I remember feeling the same way at the beginning and even throughout the term sometimes. I would recommend reviewing the lecture notes on a consistent basis and asking questions if you find that you do not understand any of the material, either by going to the prof or the TAs. Attending the tutorials and asking the TAs questions really helped. Prior to each midterm, the TAs held review sessions to clarify lecture material and to direct you to what you need to focus on for the tests, which was also extremely helpful. Moreover, the prof posts practice tests before each test so even if you have a hard time understanding the notes/lectures, as you can see, there is more than enough help and practice available to you to do well in the course (and not feel quite as lost).
I found the course to be very fair and not hard at all to do well in, especially if you are willing to put in the time and effort required to understand the material and to do the assignments/practice tests. The math concepts were relatively simple (you don't have to be strong at math - just be familiar with things like ln, log, graphs, rearranging equations etc.) and the course didn't require very much memorization which I really liked. Personally, I found the first test to be really easy, second test slightly harder (esp. the MC section) but still very fair and the exam also very fair. The assignments aren't hard, they are actually very straightforward and before each assignment is due, the TAs will go over similar if not nearly identical questions to the ones on the actual assignment - so it's not difficult to do well on them. Overall, although the material was not the most interesting to me, I really enjoyed the course mostly because the notes were well organized, the evaluations were fair and there were TAs/tutorials to help you out.
Sorry for the long post, I hope some of it was helpful. Let me know if you have any other/more specific questions