Is it normal to become *extremely* depressed when subjected to nostalgia?

I apologize in advance for what I'm guessing will be a massive comment. Lazy readers beware.

First off, I can definitely relate to the feeling of being "beyond your years," so to speak, as a child. I've done some research on it but not nearly enough studies have been done to know much definitively, so this is mostly speculation from my own experience.
They call it the curse of the gifted child because a large majority of intellectually above-average children end up feeling isolated and uninterested in age-appropriate activities. For this reason, it does seem to cause the people affected by it to feel like they've somehow missed their childhood because they spent all the years their peers spent playing being very cognitively aware, leading them to thought processes which normally wouldn't occur for years.

I obviously don't know your particular circumstances, but a lot of people get a little anxiety and depression looking back on memories as they age for various reasons, and since you've always felt cognitively ahead of your peers, it makes sense that you'd notice it earlier. For most people, it's a sort of realization of aging in itself, recognizing that they'll never actually get to go back to those times or re-do what they regret.
It does sound like your anxiety related to those memories is pretty intense and is bringing you down; sometimes people can work through it on their own and sometimes they can't, but 8 years is a long time to have dealt with it already, so perhaps if you feel like it'd be helpful, you could look into some cognitive therapy; this type of thought cycle is exactly what it was designed for. Maybe just an online support group would help. Everyone's different in what works for them.

As for your parents, realizing their mortality is also a normal part of aging that everyone goes through. I know it's a horrible thought as it wasn't so long ago that I thought, in more than just passing, that someday my parents simply wouldn't be around anymore, but that's how life goes. The trick is to not let your thoughts and worries stop you from enjoying the time you have now because eventually, you'll look back and wish you'd been more present to enjoy the things and people around you.
Best wishes,
Ace

I feel similar. As of right now I feel like I'm going through a mid-life crisis at the age of 19. Whenever I think to the past and events that I experienced, I always wish I was there instead of where I am right now. And when I smell or taste something that reminds me of my past I get very depressed and have even cried spontaneously before. I find myself walking down the toy aisle in stores and feeling hopeless and wanting to go back to being a kid again. And whenever I see kids playing It immediately puts a smile on my face that masks the sadness of never being able to do those things again.

After thinking about it very hard over the years, I think I have a mental state that hates living in the present. I desire to live in the past and the future, times that I can't reach, and nostalgia kind of makes me realize that I am stuck in the present for eternity. And the present clogs my senses and fogs my mind until before I know it, I have aged without even knowing it and begin to miss my past and want to see my future.

Basically my finite time eludes me and nostalgia reminds me that every wasted second is just as traumatic as years of negative events.

I can relate to you when you said that you had a mid-life-crisis in a way. I always felt too young and pathetic, so it's the opposite for me. I'm glad to see that I'm not the only one who felt like that when I was a child.

i can understand you. kind of. when i think about the mafia or the medieval time, i get pretty depressed too and feel, like i would be way more comfortable with living in this time.

I can relate to what you're saying thinking of past times makes me feel depressed but for me it's because I was a.much different person then, in my teens I could laugh things off but now as I get older it's a different story. For the past year it feels like I've been riding a spiral constant downward spiral and I am at that point where I feel suicidal. Like you I never had a child like mindset and this is because I grew up in an abusive home where dad beat mum and abused her emotionally as well so I had to grow up, it pains me because I never had the chance to be a "little girl" Like you I'm pessimistic at times and to be honest pessimism runs in my blood I tried the optimism thing but I got so disappointed and I don't think I'll ever recover from that feeling of shattered hopes and dreams. If you wanna talk please feel free, I could use a chat with someone in the same space as me. Oh have a nice day. :)

Maybe you have a fear of getting older? I forgot what it was called but you should try talking to a therapist about that, as well as the nostalgia.