Im only 15 and i feel so down because of this itchiness in my vagina!?

hello, im 15 and i've had thrush( well, i think its thrush) 4 times in the past year! ive now got another and its A lot worse than before, My Vagina is really red and sore and itches a little, i'm a virgin but i sometimes finger myself, not veryof-ternn. maybe once every 2months and i did this a couple of nights ago? could it be thisthat'ss causing the itch? i was also thinking it could be my diet as im not very fat (7stone) but i eatallott of sugary foods? please help.thank youu.