I have had a heavy vaginal discharge since I started my period with no pain and no odor it is with-ish and creamy. It can´t be an STD since I´m virgin?

Yeast? This may be a yeast infection, especially if you have itchiness along with the thick white discharge. Try an OTC miconasole or clotrimasole as directed and see a doc if you are no better within a week.