What is this smelly discharge from my vagina?

i am 14 years old and i am still a virgin.....i notice this the other day while i was tying my shoelaces up, theres this funny smell came from my trousers and of course when i was alone i checked my undies. i found that there this white and sort of thick discharge (cuz i can see small little chunks) and it smell horrible. i had white clear discharge before but it was odourless this time was different. Whats happen down there? do i need to go to the doctors or can i just "fix" this up myself?