That is typical of what happens at the upper level courses, for all majors. Since this is your major, you should be good at these subjects, and motivated to learn, both of which will help you. Remember to take into consideration any labs. My concern is that you are changing schools, and need to get acclimated to the campus as well as the style of teaching, which, may be different. Two sciences, one math. . . any other classes? How many total hours? I would definitely not have over 15 hours (including labs). Even if you have to take summer classes, or an extra semester, it is better than getting bad grades and setting yourself up for failure. So, you know you. Do what you need to do to have a successful first semester at the university!