Sounds like a sinus headache combined with some good old anxiety.....I know I have had sinus headaches that ibuprofen couldn't touch. Your whole head or brain feels like its swollen or something its really agonizing...The dizziness, shakiness and nausea are probably a combination of both anxiety and sinuses. I would go take you a hot shower, maybe try a sinus medication (which hasn't always worked for me everytime, so if it doesn't don't worry)...do you take any type of med to calm you, if not try doing something that really catches your attention......distract, distract, distract
Tension will cause all of those symptoms, so try to focus on just calming down, put everything else to the side and use your tools for calming yourself....I always tell myself its OK not to worry and be scared because it won't change anything, it only makes it worse. Your fear wants you to believe something wrong, when it really is just a common old sinus issues.