Last night I woke up for no apparent reason, feeling very not-tired (despite the fact that I was very tired when I went to bed). I went to the bathroom (as long as I was awake), then laid back down for a few minutes, and then I felt a strong warmth in my chest , that spread outward to both arms, about down to the elbows. It lasted about 10 minutes, then faded, and I fell back asleep. What s up with that?