Pressure on bladder

Hey all! Just had my 20 week ultra sound! Bubba is healthy. But I've noticed the past two days a real uncomfortable pressure near where my bladder is.. I have been emptying my bowels and no pain when peeing but after holding on so long throughout the ultra sound there is pressure and now a little bit of pain when I walk.. Thoughts? I've never had a UTI so I'm not sure what that would feel like..