I don’t think that we can give useful suggestions without knowing what school you are at, and at least what area you are in. Knowing your major and your courses would help also, along with how you did last year regardless of whether last year was college or high school. @publisher has asked some good questions above.
Some universities are known for grade deflation. Some majors are tough. There is an old saying that “C’s get degrees”. However, C’s in early courses can lead to worse problems in later courses that depend upon what you are learning now.