"Let not your hearts be troubled," Jesus’ prescription for your past, your present, and your future, gushes out of John 14 like water from an open hydrant. And again, near the end of this 14th chapter, He says "Let not your hearts be troubled, neither let them be afraid."
We all have issues, some ongoing, and those that pop up to scream for attention in the everyday of life. Jesus offers answers to us just as He did for the Disciples in these passages. He calls us to trust, to have an active belief; to make the choice that belief in His promises makes a difference in our issues of life.
Read the entire context, John 13 through John 17. In this story, Jesus lays out His creed as guidance for His closest followers. This discourse happens over a relaxed dinner on the most important Jewish ceremonial day of the year, Passover. This sets the scene for His arrest later in the same evening. Read all of the chapter at your leisure. In particular, in John 14, look for the promises. 1) "I go to prepare a place for you. 2) He is the Way to get there. 3) He promises answers on the Way. 4) He gives us the Comforter 5) He leaves us with His peace.
You will find even more than that. You will discover a rich relationship with Jesus that will carry you to a breakthrough in the issues you are facing today. Remember, He went to prepare a place for you and he is preparing you for that place. Stamp out your unbelief and come into His peace.