Opinion? Answers?

For the past two days that I recall, it's been hurting to pee. This isn't the first time I've had this feeling down there. Its like my pee feels like acid and barley anything comes when I go. And it's often that I've been needing to use the bathroom. I don't have any std's and my boyfriend and I have sex about 3 Times a week. What could it be? I'm supposed to start my period tomorrow too.