Definitely sounds like a mistake on your part. College is a big adjustment for a lot of people, and a really heavy course-load right off the bat is hard. With that said, you are not screwed. It is only your first semester, but you are certainly facing an uphill battle. Consider taking an easier schedule next semester, and get straight A's. Whatever you do, do NOT continue getting bad grades the next couple of semesters or you will be screwed. good luck!
The advantage of placing out of many classes is that you walk in with hours and sometimes gpa points. My advice is to take a couple of 12 hour semesters and light summer classes (in addition to research) instead of 15 or more hours in order to allow you time to study more in your classes. Also, check around before you sign up to hear who are the good professors. For me, that made all the difference. I also suggest completing one elective every semester, as well, so you have something fun to do and less stress. My favorite classes in undergrad were Art History and Existentialism.
More tips:
When it comes down to it, you have to learn to study and do whatever it takes to make an A. Figure out how you can improve. That might mean Pre-reading, reviewing notes immediately after class. Doing your hw right away, forming study groups, going to office hours, getting extra books to help you, and sitting in the front of the class.
Good luck!
ps. You are luck you took orgo first semester because you can move onto exciting upper division classes sooner. I hear Biochem is a good class to take.