Anxiety/panic attack?

The worst feeling I've experienced in a long time. Its lasted over 12 hours now. I'm pretty sure I have been having an anxiety attack. All of the symptoms are what I've feeling.
It began [technically] yesterday around 1:40pm. It began when I felt something come up in my throat. I just thought it was drainage [i've been sick lately] and I just swallowed it. But when it came up again I started feeling extremely nervous and worried. I noticed my chest was tight and it was kind of hard to breathe and swallow. That got me in a panic because I thought something deadly was going to happen, like I would suddenly stop breathing and die. I already knew that people who have attacks usually try to relax and take deep breaths. I layed on my bed and did that. It didn't really help. I started freaking out and crying. Then I tried listening to some music and [oddly] it made me feel even worse. I got light chest pains too. Then I thought throwing up would help [i was feeling nauseous anyway] I couldn't puke though. Then I started getting really hot.
I got up and went to google. I saw that breathing in a paper bag would help [it didn't.] I saw on yahoo answers that one girl would layed flat on her floor and take deep breaths through her nose.
I went and did that [on my bed instead] and I got really bad chills. I started shaking and there was nothing I could do to stop it, my teeth started chattering uncontrollably too. I just tried to stay calm and take deep breaths. Eventually I fell asleep.
When I woke up I still felt bad. My chest was heavy. I asked a question on yahoo answers and hopefully some people will give me advice.
I'm scared to goto the doctor, but if I have to I will. I feel much better than how I did when i first began. But I still feel some occasional chest pain, heaviness, and that stuff coming up in my throat.
I hope I'm not getting bad pneumonia X[