I'm sorry to hear about your problem, but I'm glad you were courageous enough to share. Although I'm not a medical prof., I'm an ex-gymnast, coach, science student and really interested in health!
Your hydration status is very important, for your overall health and esp. your urinary tract health.
If someone does not drink enough water, the kidneys will re-absorb more fluid into the blood, and as a result, less fluid will be lost as urine. If less fluid is lost as urine, that urine is going to have the same amount of wastes in a more concentrated form. More concentrated urine is darker - and a sign of dehydration. Since the bladder is like a balloon, it stetches as it fills with urine. At the base of the bladder (where the knot in a balloon is) there is a special muscle called a sphincter. When there is enough pressure on it, it sends a signal to your brain telling you to go to the bathroom! If you do not drink enough water, your bladder will not fill as quickly, but will contain more concentrated urine that sits there longer (and is more likely to be a breeding ground for bacteria). As a result, I am GUESSING that the sphincter muscle may become unconditioned to pressure. When you do gymnastics, or other activities that create pressure changes in your lower abdomen, your sphincter muscle gives out and you leak a little.
So you need conditioning for this muscle!
Try keeping a diary of how much and what you drink for a few days. Then see what you SHOULD be drinking. I find that water hydrates me the best, and I carry a water bottle everywhere. It's easy to find H20 fountains to refill at that will save you $$ (and the planet). If you bottle smells "old" or you have been sick, recycle and buy another. Alternatively, you can buy an aluminum re-usable bottle (but don't buy plastic #7 or BPA bottles).
Make a note if you drink caffeinated beverages (Coffee, tea, coke, pepsi, mountain dew and even sunkist), because they suppress the release of a hormone - ADH- in the brain that results in less water being re-absobed by the kidneys; and more going to the urine, which can cause dehydration. Caffeinated drinks are OK in moderation, but you should drink MORE water to compensate for the extra that is lost to increased urine production.
If you are suffering from urinary or bladder problems, it might be good to get checked out by a urologist or OB-Gyn, with expertise in this area. Many women and girls suffer from urinary incontinence, frequent urination and urinary tract infections. Some people are prone to these problems, but it doesn't mean you have to suffer! A good doctor can take a history of your symptoms and do a physical exam and/or tests to make sure there are no structural problems that may contribute.
Although there may be medicines that can help (Detrol, Cymbalta/duloxetine, even Phenylpropanalomine is used in puppes!), I personally think it would be best to try lifestyle changes like drinking more water and KEGEL exercises first, before meds. Cranberry Juice and cranberry supplements are also excellent for UTI health.
Good Luck and keep us posted!