Hi there, first post.

I'm still relatively new to to meditation, i'm making my way through Daniel's book as I type so i'm still not that well versed in alot of the buddhist jargon used here so excuse my rambling.

I recently got into a state during a sitting of anapanasati that I instantly recognized as a state I had experienced a few times as a child (age 7-10 is a guess) in bed. It's not something I had forgotten about and for years since, I always wondered what that 'feeling' was that I experienced.

My awareness kind of dropped into the center of my body, I became very stable in my posture and felt a slowing of time. My body felt like it was expanding but at the same time I was feeling detached and the whole feeling had a mild tint of comfortable sadness to it. I'm finding it kinda hard to put into words, i'm not sure what stage this is on the 'path'.

One personal analogy is with everytime I've done psilocybin i'm always shocked to find that i'd completely forgotten what it was like to be high and i'll say to myself "Ahhhh, so this is what this is like, i'd completely forgotten!" like the memory only works properly while in the same mind state.

I knew that I'd experienced this 'feeling' as a child but I couldn't remember what it was like till this recent experience.

Has anyone else had a similar experience of recall from childhood?

Sounds like you may have gotten absorbed into the first jhana. Daniel describes them in his book.
Nice altered states there and lots of fun when you start exploring them.
Good luck,
~D

Yes, I used to have this exact thing happen as a child laying in bed as well. It has some similarities to the 3rd vipassana jhana.

Definitely yes, I have plenty of deja-vus of my childhood when I meditate. I am not sure if this means that one's perceptive palette decreases after childhood, and that by doing vipassana it is recovered in some measure, or if it means that children are more likely to experiment and explore with their subjective states and stumble onto things that as adults we have to work hard to get to.

Mindfulness can remind me of childhood because I had less self-concepts/conditioning when I was a child. By the time we are adults we can be like conditioned robots sleepwalking through life unless we remind ourselves how reality is experience and is not concept.