Since it's still within the treatment period, I wouldn't worry too much yet, but you might be getting a fungal infection from the antibiotics.
Or you could have a urinary tract infection. Was your urine sent out for culture? I can understand why STDs would be everyone's first thought, but maybe it wasn't that.
It's Wednesday. I might give your doctor a call later today or tomorrow if it's not better. I noticed in another thread that you mentioned home testing. If you did that earlier, now would be a time to actually see a doctor since symptoms have returned. The home tests are great, and allow a lot of people to get tested who might otherwise not, and offer a lot of convenience, but sometimes, like now, you need a doctor.
Let us know how you are.