h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Your depiction of 'psychosis' after boarding the train sounds to me remarkably akin to what psychiatrists call Obsessive Compulsive Disorder. This can manifest itself in various guises and can be of intensities ranging from a mild doubt that niggles at one for longer than is healthy, or to the clinically treatable condition where one doubts ones own eyes and mind as to whether one has done or not done something that one has actually verified as having been done by checking the fact physically time and time again!
We all doubt ourselves from time to time, and this is quite normal mental behaviour. It's when such doubt becomes a chronic habit that one should check it out with one's GP.
Years ago, I had a really uncomfortable episode on Crewe station. I was to meet my (miserable old) boss there, who would board the train at Liverpool Lime St. and I would join his train at Crewe to go on to Euston Stn. I was a little late arriving in Crewe due to the road traffic, and was already in a semi-panic. I entered one of the several platforms and located the train times indicator. Spotting amongst the many departures I saw one for London on a particular platform and dashed for the bridge to cross over to that platform. I asked someone whether this was the train to Euston and got an affirmative answer.It was only when on the train I started to look for my boss, walking through the corridors, and not being able to find him. It was sheer luck that I spotted him standing up to open a window in the train on the platform back over the bridge, and that I left my train whilst it was slow enough to get off and caught his train as it was moving out!!
Phew!! He called me for all the fools in creation and never let me forget the episode. I would have been on a stopping train and should have been on the express where my ticket/seat was booked for.