Why does this illness have no discernible pattern?

I can go from feeling like I can take on the whole world one day, and suicidal the next.
Its annoying as it means there is no way to know how I'm going to be form on week to the next. Last week, I was on quite a high until about thursday when I started with a cold, but still managed to carry on with things as normal, but today, feel like crap and find myself almost at my wits end over every little thing.
I dont really have any money worries other than the usual ones everyone has, my family are all relatively sane & healthy, I have a nice home, nice kids and a loving wife.

I just happen to have a mental illness that makes me irrational at certain points. I just wish I knew when & by how much, because trying to juggle life, university and family is beginning to get a bit much at times.

I think a lot is that I am also becoming disillusioned with the UK as a whole. We have a government run by two parties that have no mandate to rule as they have no majority and a third that cannot offer an alternative to the Con-Dem's as they have elected a leader who looks like he has had a stroke! (not saying that for comic effect. I've had a number of them. Its not nice, but he looks like an idiot, not a future PM). If Harriet Harman had stood & been elected, then the Labour party would now look like a credible alternative.
Every time you turn on the TV, the government has found a new way to keep the wealthy rich and make the poor, poorer.
Normally, its the ginger haired Danny Alexander who is sent out like a lamb to the slaughter to do the treasury's dirty work, because Boy George Osbourne cant be seen to get his hands dirty when the tories have a lib dem to do it for them.
Enough for now. I'm knackered & need a kip.