Always keep 1 million in the bank is my best advice. That way you can do a lot things when needed and cover surprise cost.
That's what I've been doing wrong! I've had a million or more on my bank account maybe a cumulative 36 hours in my BB career.
I think in terms of the OP, whatever advice we give is nice and all as long as it is useful, but the important thing is for the user him or herself to figure out why their economy is unhealthy and make a long term plan to ensure it doesn't happen again. Any time you see a negative weekly profit after arena attendance, that's a huge red flag that says that what you're doing is unsustainable and there either needs to be a strong look at cost cutting or a promotion/arena expansion finishing shortly. Especially since there's always twelve economic weeks in a season but only eleven home games, so the picture in a larger view is worse than it appears.