Ok pregnant ladies need some help here?

31 weeks pregnant with little girl here. Got up this morning and when I went to bathroom, felt like I was on fire. I have been drinking plenty of water but still got something going on down there. Any suggestions to help would be greatly appreciated. Am planning to contact OB in the morning. Just need some relief tonight. Son is having his wisdom teeth taken out first thing in the morning so it will be late morning before I can get a chance to call. Any help ladies, feels like my hoo-hoo is on fire when going to the bathroom.