Why does my vagina itch so bad?! please help im scared?

ok im 13 years old and my vagina itches SO BAD!! sometimes i cry because it itches so bad... i dont have any other symptoms of a yeast infection so its not that but i do have bumps down there but i am NOT sexually active but i did masterbate with my dads electric toothbrush and my dad smokes weed so is it possible i got it from that?? and my dad extremly sexually active so isit possible for me to have gotten an std because another girl masterbated with the same toothbrush?? it immediatley started itching after i masterbated and it hasnt stop for about 3 days... please help.. what should i dooo????!!!!