Viscous pale green vaginal discharge

Patient: I have noticed a heavy amount of viscous pale green coloured varginal discharge which is causing a skin irritation because of permenent moisture….it is not offensively odourous usually a fishy smell indicates a real infection I think? I stupidly had unprotected sex a week ago with a new partner can I have picked up an STD ? Im concerned because I must watch my health as I suffer from PKD (poly cystic kidney disease) and I dont want to get another UTI ..Can I treat this with over the counter medication? I am currently in Italy on holiday and cannot get back yet to see my own GP??