I know I am a far-from-perfect writer and my verbal grammar is even more of a disaster, but let me clarify something for you--
"I could care less" isn't the phrase you are looking for. It means you do care. Sure, it doesn't imply that you care a significant amount, but regardless, there is room for you to "care less."
"I couldn't care less" is what you mean. Care factor: absolutely zero. You couldn't possibly care any less because there is nothing less than how much you care!
Yes, certain Ivy League folks have argued that Option 1 is being clever, witty, and other nonsense. But let's be real, even if it were true that some people use it in this way to be ironic, you did not know about this... you used to phrase because you thought it was correct.
Given your position and the context in which you used the phrase, I'm assuming you were some kind of journalism or lit major. For some reason this makes the entire situation way more sad for me. The college kids of your generation are the reason the college kids of mine are jobless.
♥,
C.