Hi, Marj. I know that the peace that passes all understanding lies within the Lord. I know I have received so very much peace in my life because of Him, but I also know that I could have a lot more peace if I would learn to turn EVERYTHING over to Him. I think most of us turn things over to Him and then take them back to once again worry about them. But, I'll say I've found a bountiful amount of peace that does pass understanding in my life and expect to find more.
It's a journey and a slow phase when you give yourself away. It's a slow phase to gain the understanding of the choice you made because Christ already paid. Remember this, give yourself away, knowing that you will be in a place of eternal happiness soon. :)
Your question is one that many others have in common with you. In this system of things peace really does not exist. The Scriptures are real clear that peace can only come from having a close personal relationship with Jehovah. Philippians 4:7 states: "and the peace of God that excels all thought will guard YOUR hearts and YOUR mental powers by means of Christ Jesus." Psalms 119:165 states: "Abundant peace belongs to those loving your law, And for them there is no stumbling block.." You can find this peace by drawing close to Jehovah through a deep examination of his scriptures and praying to him incessantly. (Thessalonians 5:17). Www.jw.org
God is speaking about "internal" peace. It's peace in our heart and mind. It's "peace that passes understanding" It's peace in spite of what is going on. It's beyond understanding. The mind is the biggest enemy that we have to deal with. It's our minds that continually imagine the worst scenarios and unless we allow God's peace to fill our minds, the turmoil around us will overtake us. PEACE NEEDS TO PASS UNDERSTANDING.
I have often wondered where such feelings come from. It's no because I'm righteous. It's not because I'm true. Because I have failed and made many mistakes. So I guess it's like Jesus said. The wind bloweth where it listeth, and thou hearest the sound thereof, but canst not tell whence it cometh, and whither it goeth: so is every one that is born of the Spirit. (John 3:8 KJV)