Sweetie, it's nearly impossible for us to tell you what it is. We're not doctors, we're not there to run lab tests, or see the symptoms you're describing.
There is one, and only one way you're going to get to the bottom of this...go see a doctor. Waiting and seeing isn't going to work. Trying to fix it yourself isn't going to work. Know why? You may or may not have a bladder infection. You may or may not have a yeast infection. You may or may not have an STD. If you try to treat something you don't have, you may just end up giving yourself a yeast infection, or what you do have may just get worse, or if it's the result of an STD or yeast infection, you run the risk of passing it to your partner (if you have one) by leaving it untreated, in addition to placing yourself at risk for future problems.
If it's burning when you pee, then make an appointment to see a doctor. In the meantime, drink lots and lots and lots of water. Make sure you're washing with a gentle, unscented soap, and that you're getting all the soap off before you get out of the shower/bath. Avoid feminine deoderent sprays or scented pads/tampons/panty liners.
Bottom line, go see a physician.
There's hair there for a reason!
"Never insult an alligator until after you've crossed the river." ~Oriental Proverb