I almost switched to business when I was a Mechanical Engineering major, but opted to go Civil instead. As an engineer you can be a business man (I got both Math and Business minors), but a business degree won't let you do engineering. An engineering education is as much about learning how to solve problems and developing thought process as it is actual knowledge that you will directly apply in the real world.
The best way to understand a math class is to take the next level up and the last one suddenly becomes clear. The problem is that grades don't get changed.
I took a class with 4 people in it while in college and on one test we managed a collective 99%, I got the high score at 35% and the low was about 10%. Also, in Linear Network Analysis I got a 35% on the first test and 39% on the second test. Thankfully, there was a retake exam and I pulled a 68% and somehow got a 89% on the final. The low test score was 11% of the grade, the high test was about 30% and the final was nearly 40% so I managed to pull a B out in the last couple of days. The make-up exam and final were two days apart.