My unicorn has fallen very ill. Can anyone help please?

My unicorn Gaga is very sick. He's having terrible head and chest pains and difficulty breathing and seems very tired. I tried to get him to eat, but he just isn't hungry and is too weak to chew. I fed him some rainbow broth with a dropper but it didn't seem to help any. He feels really cold and his muscles keep quivering; I feel so sorry for him. I'm going to get a bucket of warm water and wipe him off a bit to relax him and warm him up. He definitely is not resting well but he's keeping his eyes closed a lot to avoid straining and worsening his headache. I'm trying to keep him as comfortable as possible. The vet we normally consult when he becomes ill won't be in for the rest of the week, and any others don't deal with unicorns. He's never been this bad off before, and I don't know what to do. Does anyone have any ideas on how I could possibly make my poor Gaga feel better? :(