Need help

Ok well here's what's wrong.
I have been getting pains in my chest and my heart beating fast and i am attending the hospital.BTW forgot to but my age in i am 19 year old female. Anyway the hospital but me on xanax back in November an i have been taking them ever since two a day and sometimes three if its bad. I was back in the hospital last month and they gave me more xanax. I have n one left now and have been trying to get them off my own GP but she wont give them to me because she said i am to young to be on them I don't really want to be on them anyway but i haven't took xanax in the last two days an i am starting to feel kinda weird its a feeling i cant explain. I am still getting pains as well i was just wondering has anyone been through this and have any tips of what to do when the pains come .
Sorry i haven't got this worded very good but any help will do i am thinking of going for a walk this evening to see if that helps a little because its a night time it gets worse.