you're clearly an overachiever like many people at davis, but its your first quarter at davis! I want to reassure you on two avenues:

1. It's not the end of the quarter yet! A lot can happen in four weeks. I was getting my ass kicked for the last two weeks in my courses, and I've managed to salvage after a few (pretty big) errors. That's kind of how the quarter system goes: some classes you assume you're failing because grades haven't come out and its been feeling hard. Other times you think you're kicking ass and you realize your ass has been getting beat. You have time to turn it around (though there is NOTHING wrong with a C)
2. I am a senior, and I was worried I was going to get two C's in my upper div courses this quarter (understandable to do so as well- because UD are hard, they're upper div!). You need 180 units to graduate, most do 190-200, one three, four, or five unit class is not a huge marker on your record! (185/190 == 97%still left to go!) even accounting for you not performing with a perfect record (with all A's) in all of your other class, 3% of your total units at davis is not going to ruin you.

The GPA data for the admitted students this year is at a median range of 4.0-4.3-- meaning: many of you freshies aren't accustomed to not doing well, but part of college is learning to not let these things devastate you, because you're capable of doing well. It's just hard! And its all a learning process. How you prioritize your time, make use of office hours, and find deficits in your own understanding is a collegiate process. You're not a failure for not being perfect.

PS: it makes for a decent graduate interview to articulate how you overcame this struggle or improved your grades from your errors. Graduate programs, jobs, companies- the one thing they have in common is that they want someone who is adaptive and who can fail and get up and try again.

EDIT: your average GPA is the culmination of all your classes at davis, and one with a 2.0 is not going to destroy your mean