Can I use 我的上一辈子 when talking about an earlier part of my life which I almost don't recognize as mine anymore? Context: I posted a photo on WeChat of an event that happened a long long time ago to me. I was living a completely different life back then. Different country, job, I was much younger etc. It's surreal looking at the photo as it's just hard to believe that that was a period in my life.
Under the photo I left a caption 我的上一辈子. It is a kind of a simile or a metaphor, where I'm trying to express how surreal it is that that was once my life.
Anyway a Chinese friend got back to me and started explaining how it implies reincarnation and I should use a phrase more along the lines of &quot;my younger years&quot; or &quot;an earlier part of my life&quot;.
But that is not what I was trying to express. I'm not trying to express &quot;my past&quot;, I'm trying to express:

&quot;although this really happened to me it is so hard to believe that, it's as if it were a faint memory of a past life&quot;.

To native and fluent Chinese speakers, would you understand what I meant by this caption or do you agree that it is flat out wrong?
in your situation, try the idiom “恍如隔世”.
http://dict.revised.moe.edu.tw/cgi-bin/cbdic/gsweb.cgi?o=dcbdic&amp;searchid=Z00000086679
some would write it as “仿如隔世” 
here’s an example of it’s usage:
https://www.thestandard.com.hk/images/characters/20170222230555idoms.pdf
have fun :)