it couldn't have come at a worse time

Could you please explain this sentence to me

"It couldn't have come at a worse time, in the sense that with business investment weakening, and with the housing market, at least in activity terms, having turned, that's where the timing is unfortunate for us"

Does this complicated sentence simply mean: It is the worst time now because the business investment is weakening and the housing market becomes less active than ever before?

Could you please tell me more about the use of " it couldn't have come at a worse time", I just guess the meaning of this phrase according to the context, I don't understand it thoroughly.

Could I replace " in the sense that" with " in the aspects of " or " in the fact that"?

And  why the author used "where' in this sentence?

Thanks in advance.

Thank you, Mr Clive.

"Last week, I bought a new house and a new car, and my wife had twins. This morning, my boss told me that I was fired. The news could not have come at a worse time".  

According to your example, I think may be the meaning of this phrase is roughly like this: "It seems that everything is very wonderful,  then suddenly bad things happen, and you say : the bad thing couldn't have come at a worse time".  Have I gotten the right idea?

So, in the sentence about business, it is implied that the economy had been doing very well before these terrible things(weakening investment....) happened, isn't it?