Changes from HRT regimens are powerful, but gradual. I would guess that what you're feeling at two hours in is a sense of emotional relief and satisfaction with taking a major step in transition.
Most trans folks have experienced years of internal gender noise and confusion inside their heads as they struggled with uncomfortable social norms and expectations. It can take a long time to sort things out and decide in which direction you're going to move. You've made your decision, and you're now under way. That sense of decision and action feels good, and that's what I think you were feeling at the two hour mark.
Over the next weeks, months, and years, you will notice all sorts of physical and emotional changes that you will like. Most of them will develop very subtly and gradually. You may not even be aware of them for a long time until you have a sudden jolt of awareness. (Here are two from my transition: Suddenly finding yourself crying when you're watching a sad movie when you have gone through your whole adult life without crying. Unexpectedly catching sight of your reflection in a store window and being startled at how much your face or body have changed.)
Congratulations on getting started. I'm glad you're feeling good right now, but the best parts are yet to come. Buckle up and enjoy the ride!