Hi Ishiru: I would say that unless you're self-medicating in some way or other, it's unlikely that your hormone levels are changing significantly enough to produce the effect you're describing. I would be more inclined to think that it is simply a combination of spending large amounts of time wearing your seatbelt, perhaps along with the temperature & humidity (if these are high), & your desire to have more there. Our minds can play many tricks on us, especially when we want something SO badly as one does when s/he is trans. On the other hand, it is certainly within the realm of possibility that something could be going on. So, if the feeling continues & / or becomes more intense, you may want to see a doctor.