What Causes Severe Headache With Nausea?
Possible migraine headache.
Detailed Answer:
Hello and welcome,
I am sorry you are having trouble. The symptoms you are describing sounds like a migraine headache: one side of head, nausea, feeling out of it or not right.
But this shouldn't be diagnosed online - best to be seen and have a neurological exam if it reoccurs.
The sinus pressure may have tripped the headache.
Consider taking flonase (sold over the counter at drug stores) for the possible sinus infection or allergy as the flonase, which is a nasal steroid, will decrease inflammation in the nasal passages and sinuses. Takes a few days to start working.
I hope this information helps. Please let me know if I can provide further information or clarification.