Here are links to 3 articles, from PsychCentral's archives, related to the subject of painful past memories, the first by our host, Dr. John Grohol, Psy.D. Perhaps some of the information in them can be of some help:

https://psychcentral.com/blog/learni...ys-to-move-on/

https://psychcentral.com/blog/lettin...ful-over-time/

https://psychcentral.com/blog/what-r...your-life-now/

Also, since you mentioned that seeing a counselor or therapist is not really an option for you at present, one self-help technique that may be of some benefit would be what is referred to as "compassionate abiding". Here's a link to a description of the practice:

https://mindsetdoc.wordpress.com/201...e-abiding-101/

May it be of benefit.