If your physician says it is a sinus infection, it probably is -- or at the very least, it is something related to the sinuses, which can be painful and definitely can cause discomfort. If you want to be sure you have what your doc says you have, go to WebMD (www.webmd.com) and go to their symptom checker under sinus infections. Then go to their symptom checker under brain tumor. You will be comforted by what you find.
As for a brain hemorrhage, if you had one, you would have had severe bodily responses by now or you would be unconscious or even worse, so you can forget that one.
Your sinuses are air cells in your facial bones that serve to normalize air pressure. When the linings of these air cells becomes inflamed because of allergy or infection, they thicken and close off the teeny tiny air opening into the sinus cavity. The air pocket in the sinus becomes trapped, and when the external air pressure changes due to weather or altitude, the air trapped inside the sinus cannot change, so it bulges or shrinks, causing a sensation of pressure and/or pain -- and the pain can be quite intense.
There are lots and lots of home remedies, but just about the best is simply to take a couple of aspirin or Tylenol, take some pseudoephedrine (a brand name of which is Sudafed), wait about half an hour until this stuff is in your blood stream, then stand in a steamy shower for 10 or 15 minutes and deeply inhale the steam. This alone can soften the plug and help open the sinus, but in conjunction with the antiinflammatory (aspirin or Tylenol) and the decongestant, it will probably open the sinus and relieve some of the pressure. Of course it may close again if the infection persists, but you can repeat this treatment.
If your sinus infection has lasted for a month, though, you need to call your physician and tell him it is not going away, so he can determine whether you have allergies (and give you something for that) or an infection (so he can give you an antibiotic) or if you have something else causing the inflammation.
Don't worry. A massive percentage of the population of the world has had sinusitis at one point or another in their lives, and they all survived. You will too. Just try the steam/aspirin/pseudoephedrine route, and call you doc.