Answer three questions about the trade that lost, in order. "I was on the wrong side" is tautological after the fact and tells you nothing to do differently. These three separate the part you got wrong from the part you can change.
Question 1 — the read
Did the move you predicted actually happen?
Not "did it pay" — did price go the direction you called, at all, by any amount, after you entered?
Question 2 — the instrument
Would your contract have paid on a normal move for this symbol?
Compare your break-even percentage against the symbol's median open→low. TSLA's median day gives 1.39%; SPY's gives 0.38%. If your contract needed more than the median, it required an abnormal session.
Question 3 — the exit
Was there a point where you were up and did not take it?
Check the actual high-water mark of the position, not your memory of it. On a 0DTE contract this can be minutes long.
AWAITING ANSWERS
Answer all three
The verdict names one cause and one change. Most losses that feel directional are not.
Why this order. The read is first because if the move happened, direction was not the failure and no trend filter would have saved you — trend alignment was tested at n = 38,897 and returned +0.027 R with Holm p = 0.34, smaller than the spread you pay to express it. The instrument is second because it is arithmetic you can check before entry. The exit is last because it only becomes the binding cause once the first two are clean.