Im not a drug addict im 19 n i went to the doctors n he gave me some cheap cough syrup but it didnt work n ive?

*cont*been feeling dizzy and sick but not throw up sick you know like flue but i google my feelins and they said i need promethazine and they say that works alot better then wat the doctors give you but they have a hard time giving it out but my ?? is how do i get it form the doctors like wat im i suppose to say and stuff