Problem is I am wondering if my memories need to contain some sort of theme.
yes
it doesn't matter what, just give it some kind of structure. something for a reader to look forward to rather than lol random. that way you have an end goal, and not just listlessly writing stuff 'til you get bored.
like even having the memories go in chronological order is one thing you can do. continuity is good. progression is also good. you could also make the events episodic— hell you could even arc recovery in there. like writing stuff that formed your initial basis of wanting to recover, and having the overarching narrative being about seeking recovery and your views on what recovery really means, even if a lot of the memories themselves were not about recovery, but just random events that happened. that way people who read it can empathize with the character (you)
or you can write random stuff and see how it goes. i mean i'm not a writer so up 2 u
about the boring thing tho, no clue what other people see as boring i mean i've written a lot of random stuff and not many people say anything so i just assume it's boring Cx