Smelling smell that is not actually present is called phantosmia. If the smell is present in the environment, but is distorted then it is called parosmia.
Phantosmia is usually caused by brain injury or temporal lobe seizure. Given the fact that you have high blood pressure, you might want to consult with neurologist to find out if you had experienced small seizure lately, but you did not recognize the symptoms. Physical examination and visualization methods (Computer Tomography or Magnetic Resonance Imaging) might be needed to detect the previously damaged brain tissue.