I"ve had a vehicular accident and I got a little fracture on my "left hip pelvic joint" and are painful..

An anti-biotic won't help with the pain. You need to go to the hospital now-call a friend, a relative, the hospital itself. They can help you decide what to do. Its either go to the hospital or sit there and suffer. How old are you? If you really can't walk than going to the hospital is exactly what you need to do. Why do you think you need an anti-biotic? What pain reliever did they give you?