Mathmatical Difficulties

My break is over and school is back on. One of my classes is the second half of a math for elementary school teachers course. This section is also twice as long as the summer section was, so I have been excited that I will have the time to really think about what I am learning and ask myself, “How will I apply this in the classroom?” instead of just flying through in order to test on time.
After one week, my excitement has already begun to wane. I feel massive frustration right now. The content itself is nothing difficult. What causes me problems is the method. I just can’t believe how much math has changed since I originally learned. I keep reverting to old ways, and I can’t seem to internalize the new techniques, even though they are probably much more efficient and easier.
Furthering my frustration is the fact that all the classroom sections of this course are during the day, when I am at my full time job, so I had to take it independent study. I did meet with an instructor to discuss the issues I am having and she basically told me not to worry about if I get the problems right or wrong. It's only about the method, focus on learning the methods to have as a tool for teaching different learners. But how am I supposed to teach it to someone else if I don't understand it myself first?
I’m freaked out right now about teaching math someday. I'm not clear at this point why so much emphasis in this course is placed on using the specific methods outlined in the text. Does the curriculum dictate the specific method that you have to teach, or do teachers have the leeway to teach any method as long as the objectives are accomplished?
I need to find a way to just let go of my preconceived ideas of how to do this and try to put myself in the place of a student learning this for the first time. How would I want the teacher to explain this to me? I even went to the extent of buying a white board so that I could work through it as if I was explaining it to a class; sometimes teaching something helps me understand it better myself.
Letting go of the way I think things should be taught (based on the way it was taught to me) is something I need to work on, its one of my weaknesses and its not going to help me in the classroom at all- especially because the world has changed significantly since I learned, just take technology for example, I didn't learn on computers in elementary school. I need to be prepared to deal with all different kinds of learners and situations.
Maybe a good way to approach methods class is to go through the Multiple Intelligences and determine how I might teach single concept to the different types of learners. Or maybe I should create three or four imaginary students, with different learning challenges, that I can use as a practice model throughout my course. What ever I do, I think I need to place some focus on learning about differentiated instruction to help me to break out of my own patterns of thinking.
What kinds of challenges have you encountered with differentiated instruction in your classrooms?