Most of the courses in our department are rather difficult and make high demands of your time and energy; it is commensurately difficult for students to achieve a high grade. We realize that many students need to work (or at least think they need to work), but we cannot reduce our grading standards in light of that: The grades need to be assigned under uniform standards in order to be uniformly interpreted. Our expectation is that you will spend a minimum of two hours outside of class for every one hour spent in class*, and if you need to spend more time to achieve the grade you want, then plan on doing so. Thus, if your grades suffer because you are working 20 or 30 or 40 hours a week and under that schedule can't budget more time for school, then change your schedule! We realize that this will probably increase your debt load, but it should also increase what you gain from your schooling. Another option is to reduce your course load, but that will necessitate taking longer to graduate; however, read the ultimate paragraph in this opinion piece.
But perhaps you truly need to work what some faculty would see as excessive hours. There is still something under your control: your course schedule. First, do not postpone until your senior year courses you may find difficult. Consider this: If you find mathematics in high school abstruse, do you really believe that your skill and ease in handling that subject will improve through a few years of not practicing it? Unlikely. Therefore, as much as you may dislike math or science, you should take them as soon as you arrive at college, in order that you can get the general education requirements for them out of the way. Waiting until your last year--and then failing these courses--is not a wise path.
Second, do not over-budget your academic schedule. The normal load at Fitchburg State College is 15 credit hours per semester, about five courses, although lab courses carry additional credit, so in semesters with those courses you may be up to 16 or even 17 credit hours. There may perhaps be some combination of six courses that a student could take that would not lead to disaster, but none of these combinations contains a course in our department, so the bottom line is: don't take six courses if one of them is in Geo/Physical Sciences.
*In the old days the expectation used to be ten hours out of class for every three hours in class.