Hi, I have read you rant.
I'm 24 and have thoughts and grievances about my estranged mother a lot. But what I understood from my father, who at least tries to correct his wrongs, is that thoughts about parents come in waves when they are needed: when you have your own children, when you need a role model in couple problems, when you need something you had in childhood. We can learn, copy, antagonise - anyway, it's good to have insight.
The thing that ended my thoughts was to add to my life what I had as a child. I changed my content feed to what I enjoyed years ago, bought Caprisun and talked to friends 
. The weight was gone - I satiated the craving for comfort. As some say, you need to be parent to yourself when you are an adult - do what your Grandma would do for you in this situation.