I wouldn't worry about "journalling", per se, too much, especially if your concept about the significance of a "journal" is much attached to the word/name. It doesn't matter much whether what you keep going is really a "journal", per se.
In my opinion, what matters, as with running any business, is that you treat it as a business, and that means that you keep reliable written records of some kind, updating them on every day that the business has actually done any business (i.e., in this instance, every day you've traded).
Trading is a huge learning process, and it's terribly difficult (for most people, at least) to improve, without being able to study and analyse what's happened.
Becoming more successful is largely about learning to do more of "what works" and less of "what doesn't work". That means being able to analyse accurately and discover "what worked" and "what didn't work", which in turn means having good records. As long as they're good records, I don't think it matters too much whether they're specifically a "journal".