It is usually the review pattern, not your memory
A single exposure to new information—even a careful, attentive one—creates a fragile memory that decays quickly by default. This is true for almost everyone; it is not evidence of a personal weakness. The forgetting curve shows this drop-off clearly: recall falls fastest in the hours and days right after learning, unless the memory is deliberately reinforced.
If your study session consisted of reading or watching something once, feeling like you understood it, and moving on, rapid forgetting afterward is the expected outcome, not an unusual failure.
Recognition without retrieval hides the problem
It is easy to feel confident during a study session because the material feels familiar as you read it—but familiarity while looking at the source is a different and easier task than producing the same information later with nothing in front of you. That gap is often where the sense of forgetting everything actually comes from: the material was never really tested during the original session, only recognised.
This is why active recall—closing the notes and attempting the answer yourself—reveals gaps immediately that re-reading hides.
What actually fixes this
Two changes make the biggest difference: testing yourself instead of re-reading, and returning to the material again soon after first learning it rather than waiting until it has already faded. A first review within a day or two of initial learning, followed by increasingly spaced reviews, holds onto far more than a single pass ever will.
An adaptive scheduler removes the guesswork here—instead of deciding yourself when to circle back, a system like Cueable's FSRS-based scheduling times the next review close to when you would otherwise start to forget, based on how you actually performed.
What to do differently next time
After you first learn something, plan on seeing it again within a day or two, not just before the next exam. Test yourself rather than re-reading, and treat a wrong or shaky answer during that first review as useful information rather than a bad sign—it tells the system exactly what to bring back sooner.