What Causes Dizziness,vomiting And Pressure At Back Of Head?

Hi, may I answer your health queries right now ? Please type your query here...Light headed, feel like throwing up, pressure in back of head...I did take some cold medicine. some walgreens or cvs pills but now its like worse. i feel like im high of the drugs and really out of it now. I did start my mensturation. is my iron low or something?