You do the next 5 minutes, and then the 5 minutes after that, and then the 5 after that, and at some point you get to 10, and then an hour, a day, a week etc.
I read a book a little while back called Sapiens, that talked about studies done that show that peoples baseline happiness doesn't actually change very much.
Say that your baseline happiness is a 7 out of 10. You win the lottery, it jumps up to a 9 for a bit, but after a couple of years it'll even back out to a 7. You'll be richer, but no happier. The same is apparently true of losing a limb, you'll drop down to a 4, but eventually you'll adapt and end up back at 7.
It's only the case for static conditions, so for instance a degenerative condition where you are continuing to get worse, you don't get the breathing space to return to that baseline.
Now I've never won the lottery, or lost a child, or become paralysed, so it may all be a load of bollocks, but it seems to me its true for smaller stuff. I've had a massive payrise, and lost my mum, and in both those cases it was nice/ shit for a while, but a few years on I'm not any happier or sadder than I was before.
I think the point is that given time humans learn to adapt, and they can adapt to the most horrific of circumstances. As long as you can get through the initial pain, you learn to live with it. You don't forget it, you wrap it inside of you and it becomes a part of who you are, but not the whole of you.