I feel guilty in our practice

We practice the song Prayer of St Francis of Robert del Gado. It's our second practice but then we still did not sing it right. Before the practice, my plan was to polish the song and give dynamics to it. I based the dynamics from the interpretation of the Philippine Madrigal Singers. I studied about it. I marked my piece. You can see that the interpretation of Madz has full of dynamics. So I applied that dynamics to our choir. but unfortunately, i can't see them to like it. Yah, I can say that it is over - I mean, the way I teach it to the choir, the interpretation is kinda (OA - over acting).
I feel guilty, for teaching the choir that way. Because I can observe that it hurts them.
Each time we finished it singing, they are like over exhausted. They seems like to be fainting...
I think I'm a bad conductor. I need a formal education maybe. But I can't afford it anymore. I think I can learn conducting in just an experience.
I feel guilty for my singers. I might thought them the wrong ones.
I'm so sorry guys. :'(
Hope I can learn how to be a good conductor. What songs that suites our choir? How to motivate choir? How to give a right interpretation to a song?
I am so disappointed.
Not to my choir for not producing a good sound. I guess its my fault. I feel disappointed to my self.