Can STD Be Contracted Through Unprotected Sex?

Hi, I m a 18 year old female who has been having unprotected sex with a new boyfriend. The first time we had unprotected sex, I got tested for std s a few weeks later. My results came back normal (I have no std s). Recently I realized that when I pee its a weird feeling not really a burning feeling but almost. I ve been having normal discharge but after I pee it itches a little. I m naturally a over thinking type person so I m really afraid that I might have an infection or worst an std. I made a doctors appointment but that won t be for another three weeks. Can anyone tell me what they think?