It's great that you are getting so much out of your activities and enjoying yourself so much! There is no reason why hard work cannot also be fun. I also think that art and spirituality are intrinsically connected. I experience the same altered state of consciousness when acting or writing as I do when I practice something spiritual.
Natural high has such a cheesy connotation but it's a real thing and sometimes it's higher than the high you get off substances. I felt "high as hell from writing this post". You reach that state by doing what your are passionate about and really being present. So I know exactly what you mean. It is absolutely a spiritual thing.