Is this a seizure or what?

Often when I'm really stressed or bored (stuck somewhere and don't have the option of doing anything else) I'll start having a weird sensation... It's extremely hard to describe but I'l try my best. I feel some sort of ecstacy and often bend my head back and open my mouth as if I'm sucking like... the life force out of the air. Every movement I make seems to be a part of some large mechanism and it all feels good; the pleasure I have is almost sexual in nature. It's comparable to sensations while high on marijuana (I've used the drug before but haven't in over a year). Usually when I'm deep into this state I'll look like a zombie and rarely respond to anyone around me. I'm completely conscious, and it's not like I'm actually physically disabled, but i get into a "zone" that, at the moment, I just don't want to leave. I embrace it when it comes on.