How would I know if I had meningitis? Have had sinus infection. Now my face and top of head hurts. No fever or nausea. Should I be worried? Lots of pressure in head.

No meningitis. Meningitis is an inflammation of the lining of the brain which can spread to the brain at times (encephalitis). Head pain alone, specially if constant and moderate grade is far from meningitis. Severe neck stiffness, fever, nausea, altered mentation, confusion and disorientation.... These are the symptoms you would worry about.
Maybe. Sounds more like a bad sinus infection which may need medical attention. Sinus infection itself can become worse & need specific care. Bacterial meningitis is usually associated with a stiff, painful neck & fever and advances very rapidly, even over hours, and can cause confusion. That is to be feared. But most real meningitis is viral, and usually will improve over days to a couple of weeks.
Family practice . You probably have a sinus infection. Spinal meningitis usually presents with fever , headache, and neck stiffness. Confusion and altered mental status may be present. Permanent brain injury even death can occur if left untreated.
Unlikely. Head pressure, pain and history of sinus infection in the absence of fever and other systemic signs make meningitis an unlikely possibility. But, as sinus infections may not fully resolve unless aggressively treated with high doses of antibiotics, a persistent infection may present with the symptoms you describe. Do connect with your pcp.
See doctor. This would be hard to evaluate by yourself. A doctor needs to do a physical exam, and even then he/she might not be sure. But it's a good sign that you don't have fever, aren't vomiting, and hopefully no bad neck pain or stiffness. Make sure you have seen your doctor and gotten the appropriate treatment for the sinusitis, since if left untreated, you can suffer unnecessarily. Call your doctor.
See a Dr. Meningitis is a serious condition! if neck stiffness, headache, nausea, fever, vomiting, seizures, sleepiness, generally feeling bad, or skin rash appears you need to get to an er asap! meningitis is common in groups of un-immunized students living in close proximity like college dorms, the military. Failure to treat can lead to permanent complications or death.