Well, If you are anywhere from 5-19 years old then you don't know what love is. Think of that, what you felt wasn't real love. I'm sure that'll help you overcome it. If not, then *facepalm* I'm ashamed of my generation.
But, If you are 20 years or older then my condolences. Think of the reasons and benefits of not being with them or think of something they did to wrong you.
It depends on who you are and how much you truly love them. And it also depends on how you both act after the fact. It may take a few weeks or maybe even a few months but you'll find someone else who tickles your fancy.
You can laugh it off, laughter is a good medicine; find another person to fill the hole in your heart but beware if you're one of the sensitive types or person that turns into a black hole after losing your love; or just take a vacation from love to reconsider what went wrong or focus your energy on your work and individual lifestyle.