Neck Pain, a sore throat, and a loss of voice?

I think I'm sick. I have a wicked bad sore throat. I lost my appetite which has never happened before, my throat is getting filled with mucus and when i spit my throat hurts more. My nose isn't dripping though. I sing a lot and I found out that I lost my voice and it's been this way all day, but it just started this morning. I can't drink much and I can't eat at all, I only ate a tiny tiny slice of pizza today like 12 hours after I woke up because I didn't want to be malnourished. What's wrong with me... and how should i treat this? I have no clue whats wrong with me, nobody else has this and nobody else has caught it from me. I feel tired too, but no matter how hard I try I can't sleep.