Sounds like you've decided what you're going to do, which is stick with this major.
Keep with it and work hard, and you'll do well. If you don't get outstanding grades, it sounds like youa re motivated and that will at least impress some professors. Treat them like humans, not just sources of information, and you'll make friends with some of them.
Ask them to help you land internships/jobs -- some professors do more of this sort of thing than others do, once you figure out who they are you should be set. If they like you, they'll help you out. Once you get into the business world, very little depends on your academic grades.
As for surviving college:
Don't panic. You got in. You can do this.
Pay careful attention to the way you study -- few college students pay much attention to study skills. I urge you to go check out the following book: "Handbook of College Reading & Study Strategy Research" edited by Flippo and Caverly. It should be at your school's library, if it's not ask for it on interlibrary loan. Chapters 4, 5, and 9 are worth careful consideration. They outline methods of study and test prep. Implement them.
Track the length of time you spend studying each chapter using different techniques. Treat this like a workout log. If you record this information diligently, you should be able to discern patterns that will show you what your best learning style is.
I find that reading a passage then explaining it in different words aloud to myself is the best way to learn. Then, I explain it to someone else later.
Good luck -- and chin up, this is America. Hard work counts for a lot.
PS -- I have two uncles. One of them is very smart, the other has a work ethic. One of them does high-level engineering for a defense contractor and has hti a ceiling in terms of how far his career can go. The other one started a construction and development company, has built several hundred homes over the last decade, was named entrepeneur of the year in his industry, has been written about in books, and I'm guessing has a few million dollars.
Like I said, this is America -- you have to work for it.