Every so often I remember some thing that happened a while back that made me feel awful at the time. Falling down or slipping or something and hitting myself bad and being in awful pain, being in a car crash 4 years ago and still having a tiny bit of anxiety whenever another car gets a bit too close for comfort, grieving and feeling betrayed at the ending of Homestuck, which just happened a month ago! All those things, at the time, were awful. I felt sad or hurt or scared and I don't enjoy feeling sad or hurt or scared, yet every so often I remember those moments and I laugh, thinking stuff like "heheh, yeah, I could've been seriously hurt then, haha" or "pfhaha oh man, I was in so much pain at the time, heh".. Is that... normal? I imagine it's some brain processing thing, but it tends to happen to me pretty frequently.
This is pretty normal, yeah. I describe it as laughing to keep the wolves at bay. Which is how the character Abalyn describes this sort of thing in The Drowning Girl.
It's a defense/coping mechanism. Absolutely normal according to the counsors, psychiatrists and psychologists I've seen over the years. I laughed at some objectively horrifying things; hangings, decapitation, you name it.
All of this, seconded. Laughing at bad shit... happens. Your body reacts to shock and grief in weird ways. Also sometimes a thing is simultaneously 'objectively horrifying' and 'objectively hilarious.'
in my family we have a story called "the year from hell" which is a misnomer, actually, because it was actually about six months during which a ridiculously high number of horrible things happened to us. at the time it was not fun, but now that it's over we all think it's hilarious. so yeah, laughing at awful memories is normal.