What Causes Sore,itchy And Discharge In The Vagina?

i have a vaginal discharge that looks like cottage cheese. my vagina is itchy and sore. i am thinking maybe it is because i use tampons and the fact that i wash often with vaginal douches are two of the main problems. the discharge is discolored from a light yellow to a bit like yellow green, i don't know i may be color-blind. i am due for my people either tomorrow or on the 17th. is this an infection?