Totally agree with Annie, and erythromycin and cefixime aren't recommended for any STD. If you actually had an infection, you haven't cured it, most likely.
Cefixime is a sort of last resort treatment for gonorrhea, either 400 mg or 800 mg, depending on where you live, PLUS azithromycin orally once or doxy for a week, depending on where you live.
Since you took the meds, you're going to have to wait 3 weeks to get tested, or you could have a false negative test. Did a doctor give you the meds, or did you take them yourself?
The good news is that your risk is really low if it was caught quickly. It's not zero, but it's low.
My first reaction is, don't just start popping pills without any knowledge. Erythromycin and cefixime are antibiotics, were you really worried about a bacterial infection? (Plus, people aren't supposed to just randomly take antibiotics -- their overuse is creating a serious rise in antibiotic-resistant infections.)
There are timelines for taking tests for STDs. Most of them, you can't tell right away if you got exposed to anything. In general, a high-class sex worker takes better care of her health than you do of your own, so broadly speaking it sounds like you have little risk, but it would not be something anyone here could guarantee.
I'd suggest you have protected sex from now on out and get tested for the STDs in the appropriate timelines. Talk to your doctor about that. If you have a regular partner, sex should be protected during the time when you're waiting for the tests.