On the 21st I went and saw a radiologist, who in turn performed an MRI. Minutes ago they phoned me with the results. They couldn't find any evidence of "growths, masses, or blockages," but they did detect a nasty sinus infection. According to them that would explain all the headaches I've been having recently. However they're not certain what could've caused the stroke-like symptoms that lead me to schedule an appointment with them in the first place. Still, to say that I'm relieved would be understating things!