Does the past exist? Those claiming time travel would say, "yes". I have yet to see proof of that capability. Meanwhile, memories are the record of the past that are usually captivated by an instance of that memory via a picture, sound, smell, song or touch.
Some past memories are worth recalling. Others need to be forgotten for the improvement of one's mental, physical and spiritual well being. The past is finished, we should not live there but learn and progress. What matters in the now is what we do with the information and experiences of the past
combined with the outlook and forcast for the future.
In the movie The Lord of the Rings, the character Gandalf states, "All you have to decide is what to do with the time given to you."
Observing how others have handled and been victorious through the situation you are currently experiencing is a great way to appreciate and make use of The Past. Believers before the New Testament was written had and will always have the Old Testament scriptures and its lessons. Paul, in his letter to the believers in Rome, stated this idea like this - "For everything that was written in the past was written to teach us, so that through the endurance taught in the Scriptures and the encouragement they provide we might have hope." (Romans 15:4) Christians today have both the Old and New Testaments to draw from for inspiration.
Once you have found your Scripture-lesson of endurance, encouragement and/or hope - hang onto it and push through your situation 'till you see progress.
To my Christian brothers and sisters, if you have not done this already I would encourage you to start a Faithfulness Journal. Instead of building actual rock formations and naming them like the Hebrews did in the early years with God, write down in a journal the major milestones or benchmarks of faithfulness that God has shown to you. This journal can then be a source of appreciation and praise to God for His care and provision in your past and a declaration of His faithfulness for your future. Just remember to move on, make progress, be an influence and not dwell in The Past.