What do you do if your grades are bad a semester and how does that effect college?

So It's my sophomore year of high school and I just looked at my grades for this semester. It's bad. 4 C's, 1 A, 1 B, and a F. I got all A's and B's last year. I'm going to work very hard next semester, since there's nothing I can do now, and I'm really depressed. I kinda feel like I messed up my entire life. How are colleges going to see this and how is this going to effect me?