In this case I already had them- I had previously pulled a muscle that was causing a lot of pain, and a doctor inappropriately prescribed me a course of antibiotics for a physical injury that couldn't possibly be an infection, so I never took them.
It really grates me that numerous times I've been inappropriately prescribed antibiotics- but the one time I had a dangerous and debilitating bacterial infection I was unable to obtain them.
However many human safe antibiotics are legal to buy for animal use, and many countries sell oral antibiotics for human use over the counter without a prescription. Please- if anyone is reading this, don't use antibiotics inappropriately. Ideally work with a doctor,but if not make sure you actually need them, and you take a full course in the proper dose to avoid creating dangerous resistant strains.