1. Nothing lasts forever. Everything will come to pass. In five years, the things that you think matter today (like a broken relationship) will not matter that much anymore. These things will only make you stronger, and you will look back to the day when you wanted to give up, but didn't.
2. You are not alone. You have your family and friends who love and support you through the hardships and the good times. Remember the saying "No man is an island"? Well, in this case, you're not an island, because you have other people rooting for you. Appreciate them and let them know how grateful you are to have them.
3. There are so many other amazing things around you. Sure, one thing could not be working out for you today. But look around you. There are so many other things you have that others could only dream about. You may be having a rough day today, but think of the other little things that make life easier and just a little bit brighter everyday.
4. Failures don't mean you're done. Mistakes teach us lessons that we will carry with us for the rest of our lives, and that's a good thing. If you fail on something today, get back up and try again tomorrow. And then, again. And again. Failing once doesn't mean everything is over. It only means that you still have room to grow and lessons to learn.
5. You cannot find let other people (or things) define who you are. You are the only person who can make yourself truly happy. Sure, relationships are fun, and they inspire you to do better in most of the things you do. But you cannot let that certain relationship define who you are as a person. Find the love you need deep within yourself, so you can share that love with everyone around you.
6. Everything happens for a reason. Things will fall into place at the right time. Sure, it could be hard right now. But never lose hope and believe that things will be better soon. Life is really tough, but remember who you really are: you are strong and you can do awesome things. Just believe in yourself. It's going to be okay.