What Is The Clear Gel Like Substance In Urine?

Hi I'm a 14 year old female and 104 pounds . I'm only 5 foot 3 and iv had Gastritus in my stomach since I the swine flu epidemic. Last night when i was going to the bathroom clear jelly substance was in my urine. Theres usually clear substance in my underwear sometimes but this smelt kind of fruity. I have heard girls get clear fluids when they masturbate or have sex but I haven't done any of that. Thanks for your help