What Causes Headache With Nausea?

For the past two days, I've gotten a headache on my left side behind the eye and at the same time, I get a little nausea and I get sweaty. It comes and goes in waves. I've taken aspirin and ibuprofen and it helps a little. I checked my blood pressure last night and it was 117/77 so that seemed normal. So, what do think is going on.