UnWilled Sin

Is it a sin to commit wrong when one intends to help?

Today, I was in a shower when this large bully-ant kept slipping into the water line and dragged by the flow towards the drainage. After trying to flick it away a few times, I picked it up and threw it away, only to find that it was suspended in air, struggling, and not able to fall. I then saw that the poor ant had landed on a cobweb across and was being steadily pulled up by the fairly small spider.
Instinctively I needed to reach out and save 'my' ant, but seeing the spider working hard to get its meal, I became uncertain, closed my eyes tight and turned away.

In trying to save an ant, I had inadvertently provided a meal for a spider...I have held this event during my day wondering where else I 'interefere-to-help' in life and thereby set in motion such events that work against the intended compassion of my action. What is my understanding of larger forces that guides the equilibrium or the entropy of a system? or of any social, political, ecological, spiritual or universal sytems? Am I just a particle tossed by currents and energy of times, where even willed actions are transformed into unwilled events? In which case what or how do I 'will'??