Ain't it cool!
That's adrenalin and/or endorphins, the rush, a natural high. After a while, if your lucky, you wont totally loose it, but get use to it, even crave it. Some guys push the limits to keep it......... or to get it back.
I've been flying ten years and I still get it when I fly my 180 mph speed plane with over 300 flights on it. After landing, I show my hands to the guys in the pits and we all get a good laugh out of it.
That plane is flown with 100% expo to fly smooth yet still have full defections, even so, when I get the yips I can see it in the plane....funny.

At 5 flights your still a newbie, but it sounds like you know you got it so you should settle down soon...... when you reach the point, don't think about it, Just Do.