Could this be something other than an std?

It could be a urinary tract infection (uti) that you are ping back and forth to each other. But it if you both finished the whole round of antibiotics last time sorry to say but it's more likely that your "better half" is not 100percent monogamous. Don't be naive about it, you have a responsibility to protect your baby and that comes first. As for your doctor, sometimes they don't call and it's just an oversite or mistake. You need to call them and ask about the results of any tests, don't ume that no news is good news, they wouldn't give you antibiotics for nothing.