I have no real advice but agree very much with redpepper that working out what your needs and wants in life are and sticking to those is well worthwhile.
Having said that - this
It will be okay. It will always be okay because everything is movement to something better.
- I utterly disagree with. People say this sort of thing all the time - not to worry because all change is for the good.
It isn't true and for me believing it to be true is dangerous. It allows us to blind ourselves to what is going on around us in the world - to the millions of people being tortured and oppressed (quite often by those in power in the countries we live in), to the people dying of hunger, to the way that we allow outsourcing of goods and services in the name of making money to make the lives of millions just a bit worse.
More - on a personal level this insistence that everything is a change for the better puts pressure on people as individuals to not feel down. If they do feel down, not only are they letting the side down a bit, they are doing things wrong. Watching a gentle person who you've loved for years become distant, violent and aggressive is not a change for the better. It's something to live through but it isn't a change for the better. Having a partner die suddenly isn't a change for the better - it's something to live through but it isn't better.
Some people are lucky and get through these things more easily. They might have lots of loved ones around them to help or they might be particularly resilient. Others are not so lucky. For them these events can blight their lives for years and years to come. Some get depressed enough to kill themselves. Or simply live a life for decades that makes them miserable and bitter and then they die friendless and alone.
I would not get into something that hurt me with the belief that eventually things would be okay - because very often they are not okay in the end.
Be cautious. Think things through and take care of yourself and everybody around you who cares about you.