An article I was reading this morning included the thought that as we truly forgive, all memory of the wrong will disappear. So it you think you have forgiven someone or something but the memory of it keeps returning, there is more work to do. The good news is that every attempt we make at forgiveness is seeing the allness of God right where the offense seems to have taken place.
Mrs. Eddy wrote in the church Manual that 'gratitude and love should abide in every heart each day of all the years. Gratitude opens ours eyes to the presence of good. A grateful heart has no place for complaints.
Try knowing that each day is the unfoldment of God's good plan and that you are a part of that divine plan. God's day does not include dull routine, wearing frustrations, ill health, lack. It does include the knowledge that nothing can oppose or restrain the unfolding of His good. No danger is present or lurking. Nothing dangerous exists in His kingdom.
Examine the thoughts they would try to suggest something else is present and has the power to just ruin your day. That is certainly not God speaking. So you don't have to listen, believe it, or argue about it. Just dismiss it because God fills all space, so good fills all space, and there is no place for anything else to be going on.
Be at peace.