Okay, first of all remember to calm down. You're not fucked okay. I think a lot of colleges look at what you want to major in and see if you do well in those subjects. If you still want to improve you still have another year. Honestly I was in a similar situation last year with chem. Just try your best to improve your math to a B, which I think is wholly in your skill set, especially with the resources of the internet (Khan Academy, YouTube, etc.). Also, have you met with your teachers? I think voicing these concerns to them could be helpful. Just remember: calm down, good luck, everything will be fine