It was not your imagination! Starting a couple of weeks ago, the Madden-Julian Oscillation (MJO) was in the phase that gave increased convection (cloudiness and thunderstorm activity) over the Indian Ocean, and that is a phase that tends to militate against El Nino. You are correct that the wind anomalies in both lower and upper atmophere, that have been showing a clear El Nino pattern, weakened in response to this MJO factor. The Southern Oscillation Index (SOI) became much more weakly negative than it had been just a few weeks earlier. Fortunately (if you like El Nino), the much heavier flywheel of the sea temperatures, both at and below the surface, do not change very quickly, so this latest "gunshot" against the event will not make much of a dent and undo what has been building up over the last several months. Furthermore, the MJO is predicted to change phase in the next week or so, so as to be less unfavorable to the El Nino, and maybe even favorable to it. When the MJO phase is in the central or eastern tropical Pacific, it helps support (or even strengthen) an El Nino. The MJO can weaken or strengthen an El Nino (or La Nina) when it stays in the same phase for a long time, such as over 1 month. But that rarely happens, as the MJO tends to propagate around the globe every 30-60 days or so.

Congratulations on noticing this very relevant, and likely relatively brief, interruption to the atmospheric patterns defining this El Nino.