Sup fuckers. I'm a college dropout ex-gifted kid who's trying to quit being such a lazy brainlet and make something of myself.

What are the best resources for someone who got a C in freshman algebra to learn math? I'd like to go back to school for astronomy or physics in the next year or two, but I don't want to feel like a fucking retard as soon as I have to do basic math shit. Also, what kinds of math should I focus on if I want to get into those kinds of fields?