The instinct after missing a week or two of logging is to sit down on a Sunday and try to fill the gap from memory — partly to keep the journal continuous, partly out of a sense that incomplete data is worse than imperfect data. It's the opposite. Memory of mundane domains — what your energy felt like on the Wednesday eleven days ago, whether you slept well two Tuesdays back, what you ate before the dose three weekends ago — is unreliable past about five days.
The brain reconstructs rather than retrieves, and the reconstructed version blends the actual day with adjacent days, with expectations of what 'should have' happened, and with the mood you happen to be in at the moment of reconstruction. Once those backfilled entries are written into the journal they look identical to entries you wrote in real time. Your future self scrolling back to figure out a pattern three months later can't tell which entries are observed and which are confabulated, and the confabulated ones distort the pattern in ways you won't notice until you act on them.
The fix is a single rule. If the gap is more than five days, don't backfill. Mark the gap explicitly — a one-line entry like 'gap of 12 days, not filled, returning to logging today' — and start clean from the next observation.
Three reasons that works better than backfilling. One. The annotated gap is itself useful information — your future self knows there was a fortnight where logging fell off, which is a pattern worth noticing if it correlates with anything (travel, stress, dose change).
Two. The clean restart resets the discipline cheaply — no sense of 'I've ruined the dataset' that makes you stop logging altogether. Three.
The pattern reading downstream stays accurate, because every entry in the journal is real-time observed and the gaps are visible as gaps. Logging is most valuable when it's an honest record of what you actually noticed. A complete-looking journal that's half fabricated is less useful than an incomplete journal with the gaps marked.
Organisational note: the medication itself is your prescriber's call. The logging discipline is yours — and the honest version is the one that compounds.