Here's a telling piece from the business section; #1 container shipping company Maersk has stopped doing business with Iran. It was doing relatively little business before now, as many of the main ports were on a US no-go list, but even the secondary port that it was using got service discontinued.
The more widely noted piece involved the Iranian government making private foreign currency exchanges illegal; now, if you want to move in and out of the rial, you do it with a government agency. The rial has been rialing down as of late-
Early last week the rial was trading around 37,500 to the dollar, having lost about a third of its value in 10 days and two thirds in 15 months.
The level of government control is design to ration the available hard currency for things the government really needs. That rationing means that consumer imports will be hard to get through legit avenues and smuggling goods into a black market is a likely outcome.
That creates an interesting dilemma. If the government is reeling and might be ditched in favor of a different regime if things get much worse, might it be worth holding off on a preemptive strike at their nuke facilities in the hope that a more reasonable and less interested in forcing the Mahdi out of hiding by starting WW3 will come into power.
On the flipside, an Ahmadinejad regime on its last leg could try to play to the last refuge of a scoundrel and start a war with Israel and the US in order to gin up support. There's enough going on where making an informed decision is hard since there is a lot of information flowing in at once.