tightness in throat with pain in head and back

Im almost 16 and i have developed panic disorder about two-three years ago. I was on medication and everything was fine about four months ago i stopped taking my pills and for about two months everything was fine now its going back to how it used to be; tightness in my throat, feeling of losing control, not being able to breathe, sweaty palms etc. This time though i am getting on a daily basis sharp flashing pain on the sides of my head and a feeling of numbness in my face with the feeling that i am going to faint, also there are certain parts of my lower and upper back that get the same flashing pain....When this happens it lasts a few minutes and my vision gets all weird and i feel tention in my eyes.....is this still from stress??? ive told my parents but they told me it was all from the anxiety, i cannot convince myself its anxiety, i feel like im going to die or something and it scares me to a whole new level, sometimes i feel like its cancer or a tumor or something.....help?