When it comes to magik, I prefer to attempt using my own methods before I resort to spells. What I mean by this is heartbreak is a type of sadness. Try to do things you like and things that make you feel great. If that doesn't work, try a few spells on the site that bring happiness. (Small tip, Use spells you think will work. They should make sense and be something you can control. Try to avoid trick and fantasy spells. Anything That seems fake or too good to be true is to be avoided as well.)
You've been handed great advice above. Keeping positive, doing things that you enjoy that also bring both pleasure and happiness to you, etc, are all wonderful ways to counteract sadness. Plus physical exertion, going outside, and the like may also give you a little added boost. You could try aromatherapy, meditation, listening to upbeat music, singing, dancing and all sorts of other things too. Try to remember that we sometimes need to feel these things in order to grow from them. I hope you are able to discover something (or a combination of things) that will help you!