Four years on

It was four years ago today that we tearfully said goodbye to Midge our beloved Kelpie-Border Collie.
To be honest, I only found that it was today via Facebook and I didn't remember last year that I can ascertain. Of course the memories brought me to tears and sniffles.
Only four years? That was a surprise as it seemed longer.
Perception of time in relation to memory is not linear or logical. I think we always over-estimate the past. I've had a few conversations usually at work relating to now retired former work-mates and remembering when they left and working out how long ago that happened.
Memory.
It's a strange thing.
I can sort of understand computer memory: on or off; 1 or 0 although maths-related stuff doesn't normally ring my bell.
But neural memory? How can cells filled with water and other  chemicals work?
I can remember trivia for years but forget where I put my right sock 45 seconds ago.
How can I remember something that I've remembered from when I was 26 months of age?
I remember waving goodbye to my mum leaving the hospital?, nursing home?, wherever it was, after she had given birth to my brother. That was February 1956. May be it was because in this collection of images I know I fell over after running, grazing both my knees and ending up lying in a pram with my dad blowing on my knees.
Have those memories survived over 60 years due to the trauma of falling over and hurting my knees?
Are these real memories?
Or is my brain just making pictures that I think are memories?
I'll have look for a "Memory for Dummies" type book.
To add the the ever expanding list of unread books.
This will have to do in the interim... Look here