Ok so i've had this headache for 4 days and its the worst i ever had. It started out like a normal tension headache, which hurt but go away after I sleep, but the next day it was so intense i thought it was because of the medicine i was taking and i assumed i was allergic to it cuz i couldn't keep anyting down that day so i stopped taking it, but the headache came back the next day with the same intensity and even when I slept it didn't go away and today it's still here... What should I do?