Most healthy spiritual teachings encourage you to practice living in the present. The catch to this is not to let yourself get overwhelmed by negative emotions...fear, anger, guilt, remorse....all of which have their origins in the past. In other words, don't hang on to past negative emotions.
But first of all you need to acknowledge that these emotions are from the past. Note the three early lesson in A Course in Miracles: "I see only the past"; "My mind is preoccupied with past thoughts"; "I see nothing as it is now". Recognising this alerts you to the fact that you are living in the past and, furthermore, that you might have very bad attitude toward the past.
This brings us to the third part of this exploration, namely: that you might need a different attitude toward and way of looking at your past. You might ask yourself the question "what has my past done for me?" as opposed to "what has my past done to me?" This can help you to understand your spiritual journey, see yourself in a better light and live more fully in the present, being more mindful of what your past has offered to you.