First, I want to acknowledge that of course your feelings engendered by those memories can be very painful, bringing to the surface what you hope might remain unruffled by what you struggle with today. When I say what I'm going to say here, I do not mean in any way to discount any of that.
Our feelings are our feelings. Period.
I'll give you my own take on those memories, for a contrast.
My response to the Memories when they pop up is sheer gratitude for the reminders. Even when there's pain associated with them.
I am 73 years old...74 next month. I've lived thru a lot of horrendous times and agony in the process. But I am also reminded of what I wrote in the process of finding my way through it all.
Of course, most of the BIG memories of my life happened well before the internet and social media. Tho I do have a rather hefty collection of writing on paper over those years since age 20.
Sometimes the Memories do bring tears to my eyes. But as often as not they are joyful tears, not so much because they remind me of joyful times, but because of the joy I have made for myself out of those hard times.
Sometimes yes, it hurts like hell. But then I remind myself: in spite of all that (or perhaps because of it), I found my way back to joy. Every single time. No matter the depth of my despair during those times or my memories of them.
I look forward each day to seeing what remembrances FB will give me from my past. Indeed, the Memories feature is one thing I love best about FB.
And this in despite of struggling many years with deep depression, including suicide attempts -- all, obviously, unsuccessful.
Perhaps, in time, it will become your favorite as well, and you will find joy in the hardships that formed the lovely person you are.