What's wrong with me? Why do I feel sick?

All my friends except for me have recently had the flu, and I've been happy that I have avoided it so far. I haven't slept more than 5 hours in weeks because my roommates are noisy, so me feeling sick may have something to do with that. However, a few days ago my throat started hurting and it's been getting worse and worse. Now I can't eat or drink anything hot, all I want to do is sleep, and I have a stuffy nose that's draining into my throat. Every time I get out of bed to go somewhere it feels like I'm walking in a trance. The worse problem is this occasional, awful cough. It hurts, makes my chest rattle, and I'm coughing up something. It tastes metallic, but I think it's just phlegm. I do not have a fever. I keep taking NyQuil, which makes me sleep but doesn't help my symptoms. What do I have? Should I go to the doctor, or is it probably a cold I can treat myself?