What Causes Sore And Itchy Vagina?

Okay, my boyfriend and I just had unprotected sex yesterday, and today, my vagina is sore and itchy and has a burning sensation. It feels like I have to urinate, but nothing comes out. We have both had sex before with other partners and he has never had an std. I, however, have contracted Trichomoniasis, but had it treated with prescribed antibiotics. Also, I haven't had sex since I was diagnosed with that std which was almost a year ago. And once again, we are both clean. Is it possible for either of us to aquire an std? I'm extremely worried!!! Please help me. Thank you!!!