The problem is, this is a one-day shock as markets had started to price in a remain vote over the last few days, so not that unexpected. $1.39 could be a dead cat bounce, or it could be the start, rather than the end, of a long decline (as February was). It could of course be a temporary phenomenon with oil at $50 and sterling at $1.60 at the end of the year (although there is a pretty strong inverse correlation between sterling and oil prices when denominated in USD).
My personal feeling was that I expected it to go lower, more suddenly, so I'm feeling slightly relieved, being in the US right now.