How do I clear my congested chest and not get sick?

So I just started my 2nd year in college, but I am having some REALLY bad timing with my health. I've had a runny and stuffy nose for awhile now, and then I started feeling tired and achey a lot, then I had a fever a few times, and now my chest is REALLY congested. I keep coughing but nothing comes out, and I really want it out. My voice sounds very strange and makes me feel awkward whenever I have to talk in cl...I really cannot afford to miss school but it's probably getting to that point. What can I do to make myself better?