It probably needs to be more than just "cool". Volunteer at a homeless shelter or do something else that has the potential to move you to tears and make you feel your problems are just kind of whiny and insignificant. Not to belittle your pain, but to give yourself a larger view -- and to expose you to strong emotion of the cleansing kind. If you're torn up to the point of distraction about being dumped by someone who said mean things to you, then you probably need to live more. There are much bigger, grittier things going on in the world. Go take a sip from the firehose of life and forget this person.
Peace. And good luck in your journey.