With up and downs in life, it becomes harder to find and keep peace of mind. I am going through the same problem of having peace and joy inside. I was searching and asking everyone that I think would know about true peace. As per suggestion, I found a quiet place to be with myself and just try to let my worries go. But even in a quite place, I didn't experience the peace. So I kept seraching for the answer to where and how I should achieve peace.
I found out that the answer is inside me, inside you, inside all of us. It is related to your thinking and perspective. How you see the things around you and how you choose to react to them. Deep worries make peace even more difficult to achieve. That nagging voice in our head constantly reminding us of the troubles in out lives makes it more difficult to find that peace we work so hard to find. i found that peace is not an absence of chaos. But peace is the lack of troubles. There are times when it feels that everything is going wrong and there is no way to escape from constant troubles or difficult moments, so it feels like you are losing your self-confidence and spirit. The spirit is the important factor in achieving peace so we must hold on to it.
"Purpose in your heart is to walk with the spirit of God and then peace is part of life". We need to avoid the conflict situations. But we don't have to run away.