You should not have those symptoms for that long. Migraines can cause nausea and heat in the head, (don't know if you took your temp. or not), but for most people they don't go on for that long.

Don't stop looking until you find an answer. If your Dr. does not want to pursue the problem, a second opinion would be a good idea. Whatever is going on, three weeks of that is not "just" a headache.

If you have a copy of your report, see how they spell colon nervous. Is that the order the words were in and the spelling they used?

Best of luck to you,
Sam