Why cant i get wet?! help?!?

for the past 2 weeks or so i cannot get wet before sex. ive been dating my boyfriend for a year now, and im extremely attracted to him! i get horny mentally, but when we go to have sex im just not wet. i started taking a new birth control pill about 2 months ago, but this is recent. im only 14 but dont judge me for it. i dont want my sex life to suffer from this and i dont want him to think its his fault. what should i do?! :(