Vaginal Dryness in Teen Years

Patient: Dear Doctor,I am a 18 year old girl who is sexually active. Over the last 2 or 3 months I have had no lubrication in my vagina, despite being aroused, no matter what me and my partner do. We have tried extended foreplay, different types of foreplay, no foreplay, but nothing works. My boyfriend is blaming himself and it is placing stress on our relationship.I have not been pregnant, nor am I in early menopause (I hope). I have had my period since I was 10, and have been sexually active since 16.Could it have something to do with my diet, or oestrogen levels, and how do I fix it?