Once buddha was walking from one town to another town with a few of his followers. This was in the initial days. While they were traveling, they happened to pass a lake. They stopped there and buddha told one of his disciples, "I am thirsty. please get me some water from that lake there". The disciple walked up to the lake. When he reached it, he noticed that some people were washing clothes in the water and, right at that moment, a bullock cart started crossing the lake right at the edge of it. As a result, the water became very muddy, very turbid. The disciple thought, "How can I give this muddy water to buddha to drink?!" So he came back and told the buddha, "The water in there is very muddy. I don't think it is fit to drink". So, the buddha said, let us take a little rest here by the tree. After about half an hour, again buddha asked the same disciple to go back to the lake and get him some water to drink. The disciple obediently went back to the lake. This time he found that the lake had absolutely clear water in it. The mud had settled down and the water above it looked fit to be had. So he collected some water in a pot and brought it to the buddha. The buddha looked at the water, and then he looked up at the disciple and said, "See, you let the water be and the mud settled down on its own. you got a clear water. it didn't require any effort". 
Your mind is also like that. When it is disturbed, just let it be. Give it a little time. It will settle down on its own. You don't have to put in any effort to calm it down. We can judge and take best decisions of our life when we stay calm. 