(Read more: Ukraine causes risk sell-off)
Without external assistance, the economy could get much worse before it gets better. Ukraine has committed itself to repaying the $3 billion loan it received from Russia in December, which was supposed to be part of a $15 billion bailout.
The good news is that debt-to-GDP levels are less than 50 percent, and the country should be relatively cheap for the IMF to rescue. This should mean that no external debt restructuring or default is needed, according to Vadim Khramov, economist at Bank of America Merrill Lynch.
"It would be hard to explain to western creditors and Russia at the same time that the default on their bonds was necessary, when the West wants to make Ukraine "work" to avoid it falling back into Russian hands," he pointed out.
(Read more: We're broke but we won't default: Ukrainian FinMin)
The banking sector needs $3-10 billion of extra capital in 2014-16 of capital, according to Bank of America Merrill Lynch.
In the economic context, Crimea is not a huge loss: its GDP is only 3 percent of Ukraine's and it is backed in large part by government subsidies.
The new government has stopped public procurement, which has been criticized for corruption, until new anti-corruption legislation comes in. This should hopefully make the process for winning government tenders more transparent.
At the moment, subsidies on the price of natural gas (if you are a Ukrainian, you pay around 30 percent of the market rate) have helped the average Ukrainian's small salary stretch. If these are removed – as may be necessary to get an IMF loan – ordinary Ukrainians will be hit in their already small purses.
- By CNBC's Catherine Boyle. Twitter: @cboylecnbc.