I'm a huge Michael J. Fox fan. I read both of his books and find him so inspiring. He has been dealt a terrible hand and yet he seems to try to find the positives in the situation that he is in.
This quote can mean something different for everyone, and yet it means the same thing. We are all going through something. If your life is perfect, it's probably not going to be perfect for long. But whatever it is that we're going through, the hard times that we are dealing with, there is always a way through it. Nothing lasts forever and most often we will come out the other side a better person. Perhaps a different person, but a stronger person who has learnt how to deal with situations in a different way.
You don't have to accept that these negative aspects of your life are your fate. But learn from them and grow from them and figure out how these things can make you stronger. What good can come out of it? I truly believe that everything happens for a reason. And you may not figure out that reason tomorrow, or a week from now, or even 5 years from now. But at some point you will be able to say "if that didn't happen to me, then I wouldn't have this and this and this in my life". And that is what makes all our struggles worth it.