I quickly checked myself in the mirror, but couldn't see anything out of the ordinary. The men left and I resolved not to give in to any feelings of paranoia, but in the silence that followed, I became aware of some very strange atonal piano music playing in the room.
I can safely say that I have never heard piped Webern in a public convenience before and it only served to enhance the sense of unreality. Perhaps the restaurant manager was indulging his quirky and sometimes inappropriate sense of humour.
After a brief pause, the music continued. The new movement reminded me of the soundtrack to a particularly grim Eastern Bloc animated film. Outside, I could hear some innocuous folk playing in the restuarant. It was all very odd.
Then I finally realised that the music was coming from my pocket. I must have pushed an app button on my smartphone and the strange looks from the men were a perfectly rational response to a man entering the loo with atonal music emanating from his nether regions.
It was the second of two embarrassing misunderstandings this week. The first happened at my son's ninth birthday party.
For the presentation of the cake, I dimmed the lights and put on the third side of the Beatles' White Album, which begins with the song 'Birthday'. The candles were blown out and the boys seemed to be enjoying the music and having the lights off, so I left them to it.
Unfortunately, when the parents arrived, they found their sons sitting under a table in a dark room listening to 'Revolution 9' blaring out "Number nine. Number nine. Number nine. Number nine..."
I tried to explain, but I think it only made things worse.
I shall be glad when this week is over. In addition to public embarrassment, I had to spend most of Wednesday in the A&E at Haywards Heath, after my mother had fainted at a concert. Fortunately she regained consciousness quickly, saying "Well, they weren't very good singers anyway."
The doctor wanted to keep my mother in for tests, so that they could eliminate the possibility of a blood clot. Sadly, this meant spending six hours sitting in a cubicle, listening to my mother talking non-stop about other people's ailments. At one point I suggested that she should have a sleep, but she didn't take the hint.
Perhaps I'm being churlish, but six hours of "Doris with the neck needs to be near a toilet...There are a lot of coloured people working here...Brenda didn't pay me back for that pint of milk I bought...Vera's cross because the window cleaner didn't come on Thursday..." is five hours and 45 minutes more than I can take.
The one enjoyable moment this week was visiting the De La Warr Pavillion in Bexhill, just as the sun was setting over the sea.