Bliss, you are waking up into a new mode of consciousness. It may also be related to communion with a common / mass / universal [or at least species-level] consciousness. Watch episodes of the original Star Trek series where they show creatures made of energy [Obsession or Metamorphosis are good choices] and see if that looks like what you feel.

I call it the tinglies and it's usually a whole body experience but can be very head-centric at times.

Leary wrote about it in his Eight Circuits of Consciousness theory:

[From The Encyclopedia Of Record]

5. The Neurosomatic Circuit (Zen-Yoga Mind-Body-Connexion)

Concerned with neurological-somatic feedbacks, feeling high, somatic reprogramming etc. The fifth circuit, according to Leary, is consciousness of the body. There is a marked shift from linear visual space to an all-encompassing aesthetic sensory space. A hedonic turn-on occurs, a rapturous amusement, a detachment from the previously compulsive mechanism of the first four circuits. This circuit is stimulated by ecstatic experiences via physiological effects of marijuana, Hatha Yoga, tantra (Leary's name for tantra was hedonic engineering), Zen meditation, and free fall. Leary describes that this circuit first appeared in the upper classes with the development of leisure-class civilizations around 2000 BC.