Maybe your college has grade deflation. Failing grades are not C grades. I think you should calm down and go speak with your professors about things you are consistently getting wrong on tests. Maybe you aren’t studying efficiently. Maybe you are spending as much time studying easy concepts as you are difficult ones. Maybe you are not in a quiet place when you study. Maybe you have too many distractions. Are you turning off your phone? Are you part of study groups? Are you going to the campus tutoring center?
I suspect your problem lies in how you study. It might be a good idea to ask profs before every test what particular concepts need to be prioritized. You might really benefit from study groups and the tutoring center. Perhaps you are the type of student who learns best when you can bounce ideas off of others.
Meanwhile, freaking out about C’s, which are clearly not the same as and F, is not going to do you any good. You need to relax and have some perspective. You are passing. I’m not sure if you are a freshman, but a lot of freshman have terrible first semesters. Your grades are acceptable. I’m very sure there is a lot you can do to improve them. Good luck.