Antibiotics only kill strains of bacteria. If the antibiotics haven't worked, it means one of three things.
1) Your illness is not bacterial. It can be a virus, psychological or self -induced, a poison or an allergic reaction, or a metabolic problem that something in your body is not functioning properly.
2) You have what we loosely call a "super-bug" bacterial infection. The use of antibiotics is far too common, not only in medical treatments but also in the food supply and water. Mutations create new strains of life, and new bacteria can and do exist that are resistant to the various antibiotics typically used. You may need one of the lesser known new ones or there is none available to kill the bug. A different antibiotic available could be oral or by IV
3) The oral dosage was not enough and may need a strong one in high dosage that requires IV and monitoring.
The goal is to cure it, and hopefully the doctors find it.