Knowing the will of God

Knowing the will of God and acting upon it sometimes become so confusing. When it comes to decision making, how can we be in 100% certainty that the decision we are about to make is God's will?

We were driving back home on Saturday evening and saw an SUV dunked in to a road side pit. There was this old couple standing and a tow truck was pulling the vehicle off from the pit (No police on the scene). As we passed them, while we were looking at the scene, the man (probably in his late 60's) fell backward unconsciously hitting his head hard on the concrete pavement. Our immediate response was, 'Oh my God, he might have injured his head badly, Lets take a U-turn and go and see if they need any help'! But as I was looking for a way to make a U-turn, I started processing that thought in my mind, I thought to myself that there is His wife and the driver of the towing truck who could call the ambulance for them. And even if we go, the only help we could probably do is calling the ambulance. Anyways, I ended up going home without helping them and felt guilty for the rest of the day and still not able to get rid of that scene from my mind.

Was that a right decision? Does Holy Spirit help us to make a spontaneous decision or intelligent decision? From my experience, most of the spontaneous decisions I have made in life were due to the emotional pressure of the moment. Bible says, we have the mind of Christ. Then, if the thoughts are generated in the mind, and thoughts enables us to make decisions, can we say the decision we make after 'analyzing' many thoughts, is from God?

I have this struggle when it comes to 'giving'. I have made many emotional decisions in the past about 'giving'. But now a days I have been resisting such temptations. I am more towards, making wise decisions, which requires thinking. I believe God works through our mind and thoughts. Does He also work through our emotions? Most of the time I cannot trust my emotions, such as feeling sad after watching a movie for example. It wasn't real, but I still 'felt' sad. And it would be foolish to make decisions based on what I saw on the screen. My mind knows it is not real, but not my emotions.

Bible tells us about the 'renewing of our mind', which I think is replacing the error in our mind with the truth of God's word. Sometimes my emotions tells me that I am not forgiven, but the truth (reality) is I am forgiven. Sometimes my emotions tells me that I am not loved, but the truth (reality) is I am perfectly loved by my heavenly Father. In essence, most of the time, I cannot trust my emotions, so how can I make decisions based on my emotions?

"Will" is like a switch, it's either 'yes' or 'no', there is no middle ground and I believe the owner of our 'will' is us (God has given us free will). But our 'will' can be influenced by either our emotions or our thoughts (Soul consists of thoughts, will and emotions), but how do we distinguish between emotions and thoughts?
If I tend to think a lot before making a decision, I fear if I am 'over analyzing'. It becomes a little complicated. I think the fundamental question I wanted to ask is, as we live this journey of 'living by faith', how can we be sure that the decisions we make is the will of God. Should we just a take a common sense approach such as, since Christ lives in us and we have the mind of Christ, just go with our heart? And don't bother whether its an emotional decision or wise decision?