If it's a heartbreak which is common to feel sorrow for. Think of it this way, If it won't work, it won't work even though both parties try it out. It's better to find someone compatible which I think usually should not be a problem.
If it's the pain from losing money. Treat it as a lesson as every money lesson is something that will have our minds reach a higher level. When we have lots of lessons learnt, we will know how to deal with it in the future.
Stay happy by looking at the future. Think of what's that cause of the sorrowness in the first place. Write out your goals. Seek help from friends and get some time out and do something you love once in a while.