My boyfriend and I are 23 this year. We used to have sex and everything was all right. Until recently, although I want to have sex with him and I am mentally aroused, I do not seem to generate enough "water" to lubricate his penis in. This happened for 2 months already. He said my vagina is so dry that it is hardly lubricating his penis in. He doesn't want to use lubricant as he wants everything to be natural between us. However, I was very busy these 2 months travelling and working. Is that the reason that caused this? Body is exhausted? Please help, I am very worried.