>For the last 20 years, I've started my day with a single can of extremely cold Coke. If I don't have a coke within about 30 minutes of waking up, I'll get a nasty headache. I only drink coffee after drinking Coke and eating something - if I first drink coffee [or anything hot] it makes me nauseous.

Have you ever tried an ice coffee instead of a coke? I generally drink my coffee with lot of milk, otherwise I get tooth pain, then headaches from the heat.